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Abstract

The wine industry represents an important economic sector in the Mediterranean countries. Currently, grape marc is valorized for ethanol production by distillation process generating a second residue called exhausted grape marc (EGM) that should be properly managed in order to avoid any related negative impacts onto the environment. In the present investigation, an innovative strategy was proposed to convert EGM into biofuels and biofertilizers through thermochemical conversion process such as carbonization/pyrolysis technique. In order to select the appropriate operating parameters, the impact of the slow pyrolysis temperatures of EGM (from 300 to 700 °C) on biochar production yields as well as their physico-chemical characteristics were assessed. The experimental results showed that the biochars yields production decrease with increasing the pyrolysis temperature and reach a plateau above 500 °C. The biochar yield at 500 °C is around 33%, which is amongst the highest values obtained for food processing residues. The biochar physico-chemical characterization showed a higher surface area (253.4 m²/g) was obtained for the char prepared at 600 °C. However, the maximum nutrients contents, namely potassium, nitrogen and phosphorus were registered at 500 °C. Based on the biochar yields and characteristics, it seems that EGM biochar produced through slow pyrolysis at 500 °C could be considered as a promising biofertilizer for agricultural purposes.

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... The pyrolysis of exhausted grape marc could provide a sustainable approach to managing waste from the wine industry. From this standpoint, several studies were carried out to explore optimal thermal conversion pathways of winery wastes and evaluate their potential for the recovery of energy and high-added value compounds [12][13][14][15][16][17][18][19][20][21][22][23][24]. Encinar et al. [12] investigated the influence of the pyrolysis temperature and feedstocks' particle size on the quality of the biochars produced from grape marc, using a batch pyrolysis system with nitrogen as a carrier gas. ...
... Mineral analysis indicates that the Ca, P and K contents in EGM are relatively high, with a value of a few thousands of ppm, which is in the classical range found for grape marc feedstocks. In the case of Al, Fe, Mg and Si, the values measured were higher than those found in the literature [8,21]. Depending on the grape marc sources, the soil composition of the Alsatian vineyard, the harvest and collection practices, the grape harvesting age, the handling operations and the wine-making process, a variability of mineral concentrations in exhausted grape marc can be expected. ...
... %, which are slightly higher than the yields obtained in the TGA experiments. Similar char yields have been previously reported [14,21]. ...
Article
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The present study focuses on the valorisation of winery industry wastes through slow pyrolysis of exhausted grape marc (EGM). The optimal pyrolysis parameters were firstly identified by small scale experiments carried out using thermogravimetric analysis. Nine pyrolysis temperatures were tested and their influence on the decomposition of the EGM residue and biochar yield was evaluated. Then, biochar production was conducted in a pilot plant at three chosen temperatures (450, 500 and 550 °C) at which the biochar was shown to be stable. The effects of biochar application to soil with respect to plant (ryegrass) growth was also evaluated. Pyrolysis of EGM at the 450–550 °C temperature range has been shown to generate thermally stable and nutrient-rich biochars, but only the biochar produced at 450 °C showed a marked benefit effect of ryegrass growth.
... It is consumed raw and also used in the grape processing industry to produce by-products such as wine, juice, jam, and vinegar. Up to 20% of the harvested wine grape becomes waste during wine production [10]. According to the grape processing industry, about 0.3 kg of solid product is produced per kg of crushed grapes during production processes [11]. ...
... This waste originating from vineyard includes the skins, stalks, and grape seeds. These create various ecological hazards such as bad odors and surface and groundwater pollution [10]. To eliminate these effects, it is recommended as a raw material in industries such as pharmaceutical, cosmetics, feed, compost, and fertilizer [10,12]. ...
... These create various ecological hazards such as bad odors and surface and groundwater pollution [10]. To eliminate these effects, it is recommended as a raw material in industries such as pharmaceutical, cosmetics, feed, compost, and fertilizer [10,12]. Therefore, alternative assessment methods are needed to protect the environment from these wastes and reintegrate them into the economy for reuse. ...
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In this study, copper removal performance of new nanoporous carbon adsorbent (grape waste nanoporous carbon (GWNC)) produced from industrial grape processing solid waste (grape waste) under optimized conditions was investigated. The optimization of removal conditionswas determined by examining the effects ofGWNC dosage, pH, initial Cu(II) concentration, contact time, and temperature. Kinetic and isotherm data were evaluated in pseudo-first-order and pseudo-second-order kinetic models and Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models, respectively. Kinetic and isotherm data displayed that the Cu(II) adsorption onto GWNC can be well defined by the pseudo-second-order kinetic model and the Langmuir isotherm model. The diffusion mechanism of adsorption was explained using the intra-particle diffusion model. The Cu(II) removal capacity of GWNC at determined optimized conditions was determined to be 80.0 mg g−1. The calculated thermodynamic data revealed the spontaneous and endothermic nature of the Cu(II) adsorption. Desorption studies showed that H2SO4 was the effective desorption agent with the desorption rate of 89.14%. The results in this study emphasized that GWNC is an alternative effective adsorbent to commercial adsorbents for Cu(II) removal.
... Therefore, at the end of vinification and distillery process, a vast amount of several by-products is obtained, which must be treated somehow to alleviate the negative impact of their formation to the environment. Among these, grape stalks (GS), grape marc (GM) or exhausted grape marc (EGM) should be noted, as they are potential lignocellulosic feedstocks with a clear valorization towards multiple end-value-added chemicals [7,8]. For instance, GS and GM are two widely studied matrices, as well-known. ...
... These excellent energetic properties for EGM agree with the literature as well, where some authors already reported the exploitation of this matrix to produce biofuels and bio-chars, being the latter further useful as Table 1 Characterization of the winemaking wastes grape stalks (GS), grape marc (GM) and exhausted grape marc (EGM). bio-fertilizers [8,42]. Moreover, it embraces a valuable achievement in terms of sustainability, especially because of the lower harmful emissions generated after biomass combustion step. ...
Article
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This work aims to establish a novel zero-waste-based assessment for the winemaking-derived by-products grape stalks (GS), grape marc (GM), and exhausted grape marc (EGM). To this end, the application of sustainable, intensified technologies as pulsed electric fields (PEF) (3 kV/cm, 100 kJ/kg, 2 Hz, 100 ms) was firstly evaluated to recover biologically active compounds (BACs). In this regard, results from EGM should be mentioned, with an increased efficiency to up to 68 % above the conventional soaking. In addition, it was supposed the first PEF processing to this matrix, to the best of our knowledge. In parallel, with view to the desirable conditions of zero-waste, alternative valorization routes were proposed considering the in-depth characterization carried out. For instance, the exploitation of EGM towards bioenergy was firmly suggested according to its proximate and ultimate analyses, and higher heating value (HHV). Further, it was also noteworthy the amount of holocellulose and lignin present in all GS, GM, and EGM (28–35 % and 28–45 %, respectively), relevant to develop a wide range of fine chemicals as levulinic acid or furfural. Finally, the lipidic fraction, useful as food ingredient or for biodiesel production, was isolated and characterized by NMR, being remarkable the detected amount for GM (7 %). a personalized URL providing 50 days' free access to the article: https://authors.elsevier.com/a/1hPTs7tGO%7EO4A9
... As a result, BC has a higher capacity to adsorb moisture and nutrients into the soil [80,82]. The increasing temperature has the opposite effect on concentrations of acidic functional groups, volatile matter, BC yield and cation exchange capacity (CEC) [83,84]. The type of material from which the BC is produced (known as feedstock), has a tremendous effect on the content of fixed carbon, TOC (total organic carbon) and mineral elements within the BC [85]. ...
... In the same way, the aged-BC also limits underground root biomass of rice (Oryza sativa) and tomato (Solanum lycopersicum). In addition, BC can decrease soil thermal, coming from the low thermal diffusivity of BC [84]. On the other hand, popular findings show that the positive effects of BC are soil-specific. ...
Article
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Potential Role of Biochar on Capturing Soil Nutrients, Carbon Sequestration and Managing Environmental Challenges: A Review
... Therefore, at the end of vinification and distillery process, a vast amount of several by-products is obtained, which must be treated somehow to alleviate the negative impact of their formation to the environment. Among these, grape stalks (GS), grape marc (GM) or exhausted grape marc (EGM) should be noted, as they are potential lignocellulosic feedstocks with a clear valorization towards multiple end-value-added chemicals [7,8]. For instance, GS and GM are two widely studied matrices, as well-known. ...
... These excellent energetic properties for EGM agree with the literature as well, where some authors already reported the exploitation of this matrix to produce biofuels and bio-chars, being the latter further useful as Table 1 Characterization of the winemaking wastes grape stalks (GS), grape marc (GM) and exhausted grape marc (EGM). bio-fertilizers [8,42]. Moreover, it embraces a valuable achievement in terms of sustainability, especially because of the lower harmful emissions generated after biomass combustion step. ...
Article
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Valorization of agri-food residues to produce bio-based platform chemicals will enhance the transition to the bio-economy era. To this end, a sustainable process has been developed for the overall valorization of grape stalks (GS) according to a circular approach, starting from the lignin fraction to further deal with the cellulose-rich residue. This non-conventional protocol fully adheres to green chemistry principles, exploiting the so-called enabling technologies—mainly ultrasound and microwaves—for energy-saving innovative processes. Firstly, ultrasound-assisted extraction (UAE, 40 kHz, 200 W) demonstrated to be an excellent technique for GS delignification combined with natural deep eutectic solvents (NaDESs). Delignification enables isolation of the pertinent lignin framework and the potential to obtain a polyphenol-rich liquid fraction, focusing on the valorization of GS as source of bioactive compounds (BACs). Among the NaDESs employed, the combination of choline chloride (ChCl) and levulinic acid (LevA) (ChLevA) presented noteworthy results, enabling a delignification higher than 70%. LevA is one of the top-value biobased platform chemicals. In this work, a flash microwave (MW)-assisted process was subsequently applied to the cellulose-rich fraction remained after delignification, yielding 85% LevA. The regeneration of this starting compound to produce ChLevA can lead to a further biomass delignification cycle, thus developing a new cascade protocol for a full valorization of GS.
... Pyrolysis is a process by which organic materials suffer thermal degradation into smaller volatile particles, without oxygen or any other oxidants [11]. By-products are converted into oils, a mixture of gases (methane, hydrogen, carbon dioxide, and carbon monoxide), ash, mainly enriched with carbon, and heat energy [3,35,44]. Gurevich Messina et al. [45] applied copyrolysis on peanut shells and cassava starch mixtures obtaining biochar with low water and mineral content and maximizing the biooil yield. A mixture composed of 75 w % of starch and 25 w % of peanut shells led to a maximum bio-oil yield (58.2 w %), while its water content was reduced by 3.4% compared with the value expected from the weighted average of the individual results of each component in the mixture. ...
... Biofuel production can use substrates such as seeds, grains, or sugars from crops of maize, wheat, rice, and first-generation sugar. However, these conflict with food production; thus, alternative sources rich in lignocellulosic biomass such as by-products are sought [44]. The use of by-products does not enter conflict with staple foods, in addition to be low-cost substrates. ...
Article
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Over four billion tons of foods are produced annually on the planet, and about a third is wasted. A minimal part of this waste is incinerated or sent to landfills for treatment, avoiding contamination and diseases; the rest is disposed of elsewhere. The current review was aimed at broadening the panorama on the potential of agroindustrial by-products in applications such as biofuels, biomaterials, biocompounds, pharmaceuticals, and food ingredients. It also exposes the main chemical, physical, and biochemical treatments for converting by-products into raw materials with added value through low environmental impact processes. The value of agroindustrial waste is limited due to the scarce information available. There is a need for further research in unexplored areas to find ways of adding value to these by-products and minimizing their contamination. Instead of throwing away or burning by-products, they can be transformed into useful materials such as polymers, fuels, antioxidants, phenols, and lipids, which will effectively reduce food waste and environmental impact.
... At the same time, the excessive and irrational use of inorganic fertilizers may be responsible for land degradation [4], nutrients leaching from agricultural soils [5] and freshwater body eutrophication [6]. One of the promising strategies for achieving a better soil nutrient balance as well as reducing aquifer contamination is to use slow-release nutrient biofertilizers instead of synthetic industrial fertilizers [7,8] The kinetics of nutrient release decreases with time exponentially and can be well described using first-order, pseudo-second-order, diffusion and Elovich equations [8,16,22,23,26]. These equations were fitted to experimental data to estimate the leaching rates of nutrients from biochar and their availability. ...
... The lower 30 cm of the columns were filled with the reference soil (0% of biochar), whilst the upper 20 cm were filled with a biochar-soil mix in four different proportions, 0.5%, 1%, 2% and 10% of biochar ( Figure 1). The first three doses of biochar used were such that they could be applied in a realistic agronomic application [8,16], while the 10% dose was used for modeling and exploratory purposes. After filling the columns, they remained intact for 45 days to achieve homogenization between the soil and the biochar. ...
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This work examines in silico the dominant geochemical processes that control inorganic nutrients (Ca, Mg, Na, K) availability in irrigated agricultural soil amended with potassium-enriched biochar (from olive mill wastes) at mass doses of 0.5%, 1%, 2% and 10%. The geochemical modelling step was supported by analytical measurements regarding the physicochemical characteristics of the irrigation water, the agricultural soil and the biochar. Two geochemical approaches, namely equilibrium exchange (E.E.) and kinetic exchange (K.E.) models were applied and compared to assess nutrient release with an emphasis on potassium availability. Equilibrium exchange perspective assumed that nutrient release is controlled by ion-exchange reactions onto the biochar surface , whilst kinetic exchange perspective assumed the contribution of both ion-exchange and dissolution of salts. Results indicated that for the E.E. model, the soluble amount of potassium is readily available for transport within the pores of the porous media, and therefore is leached from the column within only 10 days. For the K.E. model that assumes a kinetically controlled release of potassium due to interactions occurring at the solid-solution interface, the assessed retention times were more realistic and significantly higher (up to 100 days). Concerning the applied doses of biochar, for a 2% biochar fraction mixed with soil, for example, the available K for plants doubled compared with the available K in the soil without biochar. In any case, the use of numerical modeling was proven helpful for a quick assessment of biochar performance in soil, by avoiding time-consuming and laborious experimental setups. Validation of the models by experimental data will further establish the proposed mechanisms.
... Such an ap-proach will be helpful in directing research towards the most efficient, effective and profitable solutions. In the literature there is a limited number of studies (Ibn Ferjani et al., 2019;Oh et al., 2012;Pariyar et al., 2020;Stylianou et al., 2020;Taskin et al., 2019) referring to biochar characterization aiming at both agronomic and environmental uses. ...
... The decrease in H and O contents with increasing pyrolysis temperature is quite common in the literature and is usually attributed to breakage of weak bonds in the biochar structure (Al-Wabel et al., 2013;Rehrah et al., 2016). As far as the C content is concerned, the most commonly observed behavior is its increase as a function of temperature (Colantoni et al., 2016;Gómez et al., 2016;Ibn Ferjani et al., 2019;Tag et al., 2016) and it is usually an indication of an intensified carbonization (Rehrah et al., 2016). On the other hand, C loss has also been reported (Cao and Harris, 2010;Kah et al., 2016;Lu et al., 2013). ...
Article
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This study focused on the valorization of different types of waste biomass through biochar production at two pyrolysis temperatures (400 and 600°C). The different feedstocks being used included three materials of municipal origin, specifically two types of sewage sludge and the organic fraction of municipal solid waste, and three materials of agroindustrial origin, specifically grape pomace, rice husks and exhausted olive pomace. The scope of the research was to characterize the resulting materials, in order to evaluate their possible uses in agronomic and environmental applications. Biochar characterization included the determination of several physical and chemical parameters, while germination assays were also carried out. Under the investigated conditions, both pyrolysis temperature and feedstock type appeared to significantly affect biochar characteristics, leading to the production of versatile materials, with many different possible uses. Specifically, results implied that biochars of both municipal and agroindustrial origin have the potential to effectively be used in applications including the improvement of soil characteristics, carbon sequestration, the removal of organic and inorganic contaminants from aqueous media, and the remediation of contaminated soil, with the degree of suitability of each material to each specific use being estimated to differ depending on its particular characteristics. For this reason, with these characteristics in mind, before proceeding to larger scale applications a cautious selection of materials should be conducted.
... For instance, such form may be agricultural biomass fibre such as kenaf core fibre which was used to produce activated carbon by using an acidic chemical agent [2]. Besides that, fruit waste such as citrus peel waste and exhausted grape marc from the food processing industry is also used as biomass to produce either biofuels or biochar [4,5]. Concepts of using citrus peel waste that consist of orange peels, bagasse, and seeds which are mainly carbohydrates to produce biofuels are being researched [4]. ...
... Slow pyrolysis is pyrolysis with a slower heating rate and longer residence time for biomass, approximately 0.02 • C s -1 to 1 • C s -1 for heating rate, with a residence time ranging between few hours or even days. The temperature range for slow pyrolysis fall between 300 • C and 700 • C. For fast pyrolysis, the heating rate would be above 2 • C s -1 with a short residence time below 10 s, with a moderate temperature around 300-1000 • C [3,5]. Most of the methods are discovered based on slow pyrolysis as it has more disadvantages such as time-consuming and low energy efficiency, hence methods like vacuum pyrolysis and microwave pyrolysis are introduced based on slow pyrolysis to modify the weaknesses. ...
Article
The current environmental pollution and global warming may cause a serious ecological crisis. The conversion of renewable resources, especially from biomass could be a promising option to alleviate this crisis. Traditionally, carbon produced from petrochemicals and coal are typically using large amount of energy and produce substantial quantities of pollutants. There is a need to develop alternative and effective methods to synthesize carbon from renewable resources with high performance and minimal environmental impact. Biochar is a rich carbon material derived from plant-based biomass. Biochar is one of the most ideal materials in various applications by considering it is low thermal conductivity, high porosity, high surface area, renewability, high stability, high carbon content and bulk density. In this regard, biochar has been widely recognized as the suitable candidate for sustainable carbon material. Thus, in this review, recent progresses towards the applications of biochar-based materials in various applications, such as wastewater treatment, soil amendments, catalyst or catalyst precursors and energy storage, are summarized and discussed. The various sources of biomass, synthesis techniques, and the effects of various factors involved in the carbonization process to generate different physicochemical properties biochar from the biomass is elaborated. Also, this review is highlighting the characteristics of the biochar and the carbonization mechanisms of different synthesis technologies. This review shows the great potential of different applications of biochar, which is expected to simulate new development to promote the use of biochar materials to achieve a sustainable environment and circular bio-economy.
... Casazza et al. [12] considered that GP biochar is a good source of graphitic carbon with higher calorific value with respect to the initial grape waste, and applicable for energy production. GP biochar has also been considered as a potential biofertilizer or for undergoing direct and efficient gasification [20,23]. Moreover, Brachi [24] has recently investigated the synthesis of fluorescent carbon-based quantum nanodots (CQDs) through GP slow pyrolysis in the presence of a catalysis, with successful results. ...
... The higher abundance of the acid in AP compared to TL, could be attributed to an almost complete degradation of hemicellulose during the pyrolysis process (400 °C), which could not be fully accomplished in torrefaction (225 °C). Hemicellulose and cellulose degradation also resulted in sugars (ii), such as 1,4:3,6dianhydro-α-D-glucopyranose (11), D-allose (19), and levoglucosan (23), the latter being the second most abundant product in both TL and AP (see Fig. 4). As can be observed, monosaccharides were more abundant in TL than AP, due to its low heat stability [22], that lead to the formation of compounds such as 1-hydroxy-2-propanone (1) [42] and water, the aqueous medium of TL and AP. ...
Article
Wine production generates huge amounts of residues, with grape pomace (GP) being the main solid waste. This work attempted to determine whether the use of thermochemical treatments (pyrolysis (400 °C) and torrefaction (225 °C)) are suitable processes to transform GP to a value-added compounds source, paying special attention to phenolics. GP management through thermochemical treatments could then provide ecological and economic benefits. Composition of the liquid fractions was determined by GC–MS. Phenolic quantification was performed using Folin-Ciocalteu (FC) and DPPH assay. Firstly, the suitability of these methods was discussed: DPPH assay was used to quantify phenolics in all the samples; however, in FC method, reducing sugars could interfere in the measurement. The results showed that phenolics were mainly concentrated in the non-aqueous phase of bio-oil (pyrolysis process). It was also observed that these compounds not only came from the GP composition, but from lignin devolatilization during the thermochemical process. Apart from phenolics, bio-oil was also composed of other products, such as acetic acid or levoglucosan. Therefore, this study showed that intermediate pyrolysis is a suitable treatment to add value to GP within a biorefinery concept, turning the winemaking waste into a potential source of antioxidants, together with other value-added compounds.
... The biowaste can be converted into the high value-porous activated carbon with large speci c surface area that is commonly used for several kinds of applications such as adsorbent [16,17], catalyst [18,19], to energy storage systems [20][21][22][23]. Compared to commercial carbon materials, activated carbon-based biowaste can be synthesized by the facile process through hydrothermal [24,25], chemical activation [26-28], or pyrolysis carbonization [29][30][31]. Recently, activated carbon-based biowaste materials by facile preparation have been studied for microwave absorber application. ...
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A well-developed porous activated carbon materials were synthesized from palm kernel shell (PKS) waste through the facile carbonization process with several KOH concentration, and the microwave absorbing performance were studied in the X-band range. The XRD and EDX measurement results confirmed the transformation from crystalline structure to the amorphous structure of cellulose of PKS materials with the higher carbon content. The BET analysis measures the pore size between 2–4 nm and a specific surface area between 554–825 m ² /g. All activated carbon materials show the improvement of microwave absorbing performance compared to its hydro char or raw PKS materials, with the highest minimum return loss and frequency bandwidth of -37.85 dB at 11.02 GHz and 900 MHz, respectively, for activated carbon with only KOH concentration of 10%. The porous structure of AC-based PKS is benefitted to give better impedance matching and dielectric loss capacity to enhance the microwave absorbing performance of AC-based PKS waste. This observation indicates that the activated carbon can be synthesized with a facile process from PKS waste and expands the possible utilization of AC-based PKS waste as the prospective microwave absorber materials for electronics and telecommunication devices.
... jp/ en/) with an external heating mechanism for cattle manure, chicken manure, and bamboo, at a carbonization temperature of approximately 400-500 °C for 2 h. A rotary kiln carbonizer (MES50, Kanazawa City, Ishikawa, Meiwa Co. Ltd., Japan) with an internal heating mechanism was used for slaughterhouse wastewater, rice husk, and woodchip carbonization at 400-500 °C for 30 min according to procedures outlined by Ferjani et al. (2019) and Song et al. (2012) (Suppl. Table 5 Additional information). ...
Article
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This study investigated the effect of the interaction between wood vinegar and biochar feedstock on total biomass, fruit weight (yield), and sugar content of tomato plants ( Solanum lycopersicum L . ). An experiment was conducted in two locations with six different biochar types produced from either plant or animal feedstock. Each biochar was incorporated into soil (1:2500 g/g) along with chemical fertilizer. Wood vinegar was diluted with water (1:200 mL) and applied once weekly for the vinegar treatment. Biochar application resulted in a higher yield and biomass of the chicken manure biochar owing to its high ammonium-nitrogen content. Vinegar application increased the yields of the plant feedstock, which was particularly evident for most of the yield parameters with the bamboo biochar. Regardless of treatment, yield and biomass were not significantly different between the animal and plant feedstock. The sugar content was higher for the chicken manure and animal litter biochar, which was attributed to better pH conditions. The combination of plant feedstock biochar and vinegar application for improving the yield of tomatoes is promising. In contrast, vinegar application could potentially limit the yield and fruit sugar content of tomato plants treated with animal feedstock biochar. Highlights • The soil was amended with biochar, with or without vinegar application. • The chicken manure biochar plants had the highest yield and biomass. • Vinegar application increased the yield of the plant feedstock. • Plant and animal feedstock plants had similar yield and biomass. • The pH of the animal feedstock was better because of higher CO 2 and MgO contents. • Fruit sugar content for animal feedstock plants was better due to higher phosphorus.
... Furthermore, it is worth noting the importance of the exhausted grape marc (EGM) produced in distilleries. EGM still represents an underexplored feedstock, although its valuable energetic properties in the development of some bio-oils and bio-chars are well known (Ibn Ferjani et al., 2019, 2020. Moreover, some authors have reported the important bioactive compound (BAC) content found in EGM, mainly in the form of polyphenols (Salgado et al., 2014;Tacchini et al., 2019). ...
Article
The circular economy considers waste to be a new raw material for the development of value-added products. In this context, agroindustrial lignocellulosic waste represents an outstanding source of new materials and platform chemicals, such as levulinic acid (LA). Herein we study the microwave (MW)-assisted acidic conversion of microcrystalline cellulose (MCC) into LA. The influence of acidic catalysts, inorganic salt addition and ball-milling pre-treatment of MCC on LA yield was assessed. Depolymerization and disruption of cellulose was monitored by FTIR, TGA and SEM, whereas the products formed were analyzed by HPLC and NMR spectroscopy. The parameters that afforded the highest LA yield (48 %, 100 % selectivity) were: ball-milling pre-treatment of MCC for 16 min at 600 rpm, followed by MW-assisted thermochemical treatment for 20 min at 190 °C, aqueous p-toluenesulfonic acid (p-TSA) 0.25 M as catalyst and saturation with KBr. These optimal conditions were further applied to a lignocellulosic feedstock, namely melon rind, to afford a 51 % yield of LA. These results corroborate the suitability of this method to obtain LA from agroindustrial wastes, in line with a circular economy-based approach.
... Therefore, the effects of the secondary reaction become significant, while at a low heating rate biochar is produced more [25]. Ibn Ferjani et al. showed that the biochar yield decreased with temperature and plateau at 500°C, the biochar yield was lowered at a high residence time [26]. The volatile matter is the matter loss when biomass is subjected to thermal degradation. ...
Article
Biochar is a high carbon content organic compound has potential applications in the field of energy storage and conversion. It can be produced from a variety of biomass feedstocks such as plant based, animal based, and municipal waste at different pyrolysis conditions. However, it is difficult to produce biochar on a large scale if the relationship between the type of biomass, operating conditions, and biochar properties is not understood well. Hence, the use of machine learning based data analysis is necessary to find the relationship between biochar production parameters as well as feedstock properties with biochar energy properties. In this work, a rough set-based machine learning (RSML) approach has been applied to generate decision rules and classify biochar properties. The condition attributes were biomass properties (volatile matter, fixed carbon, ash content, carbon, hydrogen, nitrogen, oxygen) and pyrolysis conditions (operating temperature, heating rate residence time) while the decision attributes considered were yield, carbon content, and higher heating value. The rules generated were tested against a set of validation data and evaluated for its scientific coherency. Based on then decision rules generated, biomass with ash content of 11 to 14 wt%, volatile matter of 60 to 62 wt% and carbon content of 42 to 45.3 wt% can generate biochar with promising yield, carbon content and higher heating value via pyrolysis process at operating temperature of 425°C to 475°C. This work provided the optimal biomass feedstock properties and pyrolysis conditions for biochar production with high mass and energy yield.
... The biochar yield was found to be maximum at 300 and 400 °C, or around 65.8% and 59.1%, respectively, when exhausted grape marc was subjected to biomass pyrolysis temperatures of 300 °C to 700 °C. However, at temperatures of 500 °C and 700 °C, biochar yield significantly decreased, with 33.8% for the former and 30.9% for the latter (Ferjani et al. 2019). ...
Article
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Climate change issues are calling for advanced methods to produce materials and fuels in a carbon–neutral and circular way. For instance, biomass pyrolysis has been intensely investigated during the last years. Here we review the pyrolysis of algal and lignocellulosic biomass with focus on pyrolysis products and mechanisms, oil upgrading, combining pyrolysis and anaerobic digestion, economy, and life cycle assessment. Products include oil, gas, and biochar. Upgrading techniques comprise hot vapor filtration, solvent addition, emulsification, esterification and transesterification, hydrotreatment, steam reforming, and the use of supercritical fluids. We examined the economic viability in terms of profitability, internal rate of return, return on investment, carbon removal service, product pricing, and net present value. We also reviewed 20 recent studies of life cycle assessment. We found that the pyrolysis method highly influenced product yield, ranging from 9.07 to 40.59% for oil, from 10.1 to 41.25% for biochar, and from 11.93 to 28.16% for syngas. Feedstock type, pyrolytic temperature, heating rate, and reaction retention time were the main factors controlling the distribution of pyrolysis products. Pyrolysis mechanisms include bond breaking, cracking, polymerization and re-polymerization, and fragmentation. Biochar from residual forestry could sequester 2.74 tons of carbon dioxide equivalent per ton biochar when applied to the soil and has thus the potential to remove 0.2–2.75 gigatons of atmospheric carbon dioxide annually. The generation of biochar and bio-oil from the pyrolysis process is estimated to be economically feasible.
... This production of ethanol by grape marc generates another residue, i.e. exhausted grape marc (EGM). Ferjani et al. (2019) studied the utilization of EGM to produce biofuel and biofertilizer via pyrolysis. Similarly, various studies have been carried out on the recovery of grape marc through the pyrolysis technique (Xu et al., 2009;Casazza et al., 2016;Khiari and Jeguirim, 2018). ...
Article
Circular bio-economy is a significant approach to resolving global issues elevated by environmental pollution. The generation of bioenergy and biomaterials can withstand the energy–environment connection as well as substitute petroleum-based materials as the feed stock production, thereby contributing to a cleaner and low-carbon-safe environment. Open discarding of waste is a major cause of environmental pollution in developing and under developed countries. Agricultural bio-wastes are obtained through various biological sources and industrial processing, signifying a typical renewable source of energy with ample nutrients and readily biodegradable organic substances. These waste materials are competent to decompose under aerobic and anaerobic conditions. The projected global population, urbanization, economic development, and changing production and consumption behavior result in bounteous bio-waste production. These bio-wastes mainly contain starch, cellulose, protein, hemicellulose, and lipids, which can operate as low-cost raw materials to develop new value-added products. Thus, this review discussed specifically the agricultural waste and valorization processes used to convert this waste into value-added products (biofuel, enzymes, antibiotics, ethanol and single cell protein). These value added products are used in the supply chain and enhance the overall performance of agriculture waste management, execution of circular bio-economy has attained significant importance and it explains a closed-loop system in which the potential resources remain in the loop, allowing them to be sustained into a new value.
... Also, biochar can effectively improve soil structure and fertility, reduce greenhouse gas emissions and alleviate the adverse effects of different stresses due to their high stability and beneficial physicochemical properties (Oliveria et al., 2017;Pariyar et al., 2020). Generally, sustainable agriculture can be achieved and evolved by producing biochar from agriculture residues and returning it to the soils (Ibn Ferjani et al., 2019). ...
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The organic amendment of degraded soil in South East of Tunisia was used to restore the chemical, and physical properties of soil quality investigated in this study. Biochar derived from pyrolyzed green waste at 360°C was used like organic amendment. Nines randomized plots with one square meter of the area of each plot in three replicates have been installed in the Institute of Arid Area in Mednine South East of Tunisia, with two rates of biochar 20 and 40 t/ha were investigated: 20 tons/ha (B20) (2 kg/m²) and 40 tons/ha (B40) (4 kg/m²). The results showed that biochar had a positive effect on soil's physical and chemical properties compared to non-amended soil (Untreated soil). Biochar supply at rates of 20 and 40 tons/ha, causes a decrease in electrical conductivity to achieve 2.66 mS/cm for the B40 dose after 1 year of amendment, also a decrease in the bulk density at the surface layer (0-20 cm) has been registered, the total porosity which was decreased with depth. The hydraulic conductivity is favored by the incorporation of biochar in the soil which increases the volume of voids and tends to create preferential flow paths.
... These results indicated the amorphous nature of KB and reduced sp 2 domains in KB carbon structure, whereas PB ratio indicated its crystalline nature and increased sp 2 domains of graphite structure [28]. Raman spectra of KB exhibited very broad peaks (Fig. 2 (a)), and this behavior is basically owing to the presence of amorphous carbon structures in a high proportion [29]. Whereas sharp peaks of Raman spectra in the case of PB is attributed to the crystalline carbon form. ...
Article
This study demonstrates two sustainable processes to produce electroactive biochars and their application in electroactive constructed wetlands (CWs) providing a circular route for biomass utilization and technology up-gradation for wastewater treatment along with electricity generation. With the use of Canna indica biomass generated CWs operation, the current study produced two different biochars that differ in their physico-(electro)chemical properties related to the preparation method used. This study used plasma based processing to produce ultrafast biochar (PB) within a few minutes resulting in more crystalline biochar with high electrical conductivity compared to the amorphous material produced by using the drum kiln processed biochar (KB) method. These biochars were used in developing electroactive constructed wetlands coupled with microbial fuel cells (CW-MFC) and were operated in batch mode together with commercial granular graphite (GG) substrate-based CW-MFC as control. PB was developed from high-temperature plasma processing in just 6.0 minutes, whereas KB was prepared in bulk amount from natural combustion process through kiln method and took 3-4 days before final biochar preparation. Electrical conductivity (EC) of the biochar and GG material were found to be in the order of PB>GG>KB, indicating PB as a highly conductive material that assisted in microbial electron transfer. Accordingly, the highest current and power densities of 628 mA/m³ and 126 mW/m³, respectively, were also achieved with PB. The highest COD removal was found in CW-MFC-GG microcosms of 72.42 ± 2.61 % followed by CW-MFC-KB and CW-MFC-PB of 72.32 ± 2.98 % and 59.91 ± 3.21 %, respectively.
... phosphorus (0.1-0.6%), nitrogen (0.5-2.7%), and organic carbon (40.2-58.2%) [158][159][160]. Moreover, del Pozo et al. (2021) investigated the recovery of phenolic compounds through the pyrolysis process as an alternative to conventional extraction [161]. ...
Article
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The wine industry is one of the most relevant socio-economic activities in Europe. However, this industry represents a growing problem with negative effects on the environment since it produces large quantities of residues that need appropriate valorization or management. From the perspective of biorefinery and circular economy, the winery residues show high potential to be used for the formulation of new products. Due to the substantial quantities of phenolic compounds, flavonoids, and anthocyanins with high antioxidant potential in their matrix, these residues can be exploited by extracting bioactive compounds before using the remaining biomass for energy purposes or for producing fertilizers. Currently, there is an emphasis on the use of new and greener technologies in order to recover bioactive molecules from solid and liquid winery residues. Once the bio compounds are recovered, the remaining residues can be used for the production of energy through bioprocesses (biogas, bioethanol, bio-oil), thermal processes (pyrolysis, gasification combustion), or biofertilizers (compost), according to the biorefinery concept. This review mainly focuses on the discussion of the feasibility of the application of the biorefinery concept for winery residues. The transition from the lab-scale to the industrial-scale of the different technologies is still lacking and urgent in this sector.
... Meanwhile, fast pyrolysis involves heating rate of >2 • C/s and residence period of less than 10 s (Dai et al., 2020b). The temperature range for slow and fast pyrolysis are 300-700 • C and 300-1000 • C, respectively (Foong et al., 2021;Ibn Ferjani et al., 2019). Sakhiya et al. (2022) prepared biochar from rice straw with slow pyrolysis in a batch-type pyrolysis reactor from 300− 500 • C with a residence time of 60 mins and a heating rate of 10 • C/min. ...
Article
The valorization of biochar as a green and low-cost adsorbent provides a sustainable alternative to commercial wastewater treatment technologies that are usually chemical intensive and expensive. This review presents an in-depth analysis focusing on the rice straw-derived biochar (RSB) for removal of various types of contaminants in wastewater remediation. Pyrolysis is to date the most established technology to produce biochar. Subsequently, biochar is upgraded via physical, chemical or hybrid activation/modification techniques to enhance its adsorption capacity and robustness. Thus far, acid-modified RSB is able to remove metal ions and organic compounds, while magnetic biochar and electrochemical deposition have emerged as potential biochar modification techniques. Besides, temperature and pH are the two main parameters that affect the efficiency of contaminants removal by RSB. Lastly, the limitations of RSB in wastewater remediation are elucidated based on the current advancements of the field, and future research directions are proposed.
... The elements such as C and N in biochar differed significantly while obtained from pine trees, poultry manure, and peanut husk at 400 and 500 • C, respectively (El-Bassi et al., 2021). Furthermore, transferable phosphate, potassium, calcium, and magnesium were significantly higher in biochar produced at 500 • C than in biochar produced at 400 • C (Ferjani et al., 2019). The deviation was primarily associated with the high pyrolysis temperature, which enhanced raw material mineralization besides reduced CEC. ...
Article
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A number of anthropogenic and weathering activities accumulate heavy metals in soils, causing adverse effects on soil characteristics, microbial activity (diversity), agricultural practices, and underground aquifers. Controlling soil heavy metal pollution is difficult due to its persistence in soils, resulting in the deposition and transmission into the food web via agricultural food products, ultimately affecting human health. This review critically explores the potential for remediation of metal-contaminated soils using a biochar-based responsible approach. Plant-based biochar is an auspicious bio-based residue substance that can be used for metal-polluted soil remediation and soil improvement as a sustainable approach. Plants with rapid growth and increased biomass can meet the requirements for phytoremediation in large quantities. Recent research indicates significant progress in understanding the mechanisms of metal accumulation and contaminant movement in plants used for phytoremediation of metal-contaminated soil. Excessive contamination reduces plant biomass and growth, which has substantial hyperaccumulating possibilities and is detrimental to the phytoremediation process. Biochar derived from various plant sources can promote the growth and phytoremediation competence of native or wild plants grown in metal-polluted soil. Carbon-enriched biochar encourages native microbial growth by neutralizing pH and providing nutritional support. Thus, this review critically discusses the influence of plant and agricultural waste-based biochar on plant phytoremediation potential in metal-contaminated soils.
... They obtained highest biochar yield of 37.71 wt% at 300°C. Ferjani et al. (2019)., investigated the effect of pyrolysis temperatures, ranging from 300°C to 700 C on exhausted grape marc (EGM) on the biochar yield and physicochemical changes after undergoing the thermal conversion process. They found that at 300°C and 400°C, the biochar yield obtained were highest and were in the range of 65.8 %-59.1%, ...
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The excessive dependency on fossil fuel resources could be curtailed by the efficient conversion of lignocellulosic biomass. Biochar, a porous carbonaceous product synthesized exploiting thermochemical conversion pathway, could be an environment-friendly replacement of fossil fuel resources. Slow pyrolysis, a sub-class among various thermochemical conversion techniques, has gained immense popularity owing to its potential to convert biomass to biochar. Furthermore, biochar obtained as the by-product of slow pyrolysis has attracted enormous popularity due to its proven role and application in the multidisciplinary areas of engineering and environmental remediation applications. The physicochemical quality of biochar and its performance is significantly dependent on the feedstock type and pyrolysis process parameters. Therefore, further experimental research and investigations in terms of lignocellulose biomass type and pyrolytic process parameters (temperature, heating rate and reaction time) are essential to produce biochar with desired physicochemical features for effective utilization. This review presents an updated report on slow pyrolysis of lignocellulosic biomass, impact of different pyrolysis parameters and degradation pathway involved in the evolution properties of biomass. The influence of the feedstock type and lignocellulosic composition on the biochar properties are also discussed meticulously. The co-relationship between biochar yield at different pyrolysis temperatures and the development of textural properties provides valuable information for their effective utilization as a functional carbon material. Additionally, an extensive study was undertaken to collate and discuss the excellent physicochemical characteristics of biochar and summarizes the benefits of biochar application for diverse industrial purposes. Biochar is acknowledged for its excellent physicochemical properties owing to the thermal treatment and as a result its prospective diverse industrial applications such as for soil treatment, carbon sequestration, adsorbent (wastewater treatment or CO 2 capture), producing activated carbon for gold recovery, energy storage and supercapacitor are summarized systematically in this review paper. For instance, biochar when applied in soil have shown improvement in soil respiration by 1.9 times. Furthermore, biochar when used to capture CO 2 from flue gas stream under post-combustion scenario has demonstrated superior capture performance (2.8 mmol/g) compared to commercial activated carbon. This paper identified the knowledge gaps and outlooks in the field of the advancements of biochar from slow pyrolysis for targeted engineering applications mainly in the field of environmental remediation and energy harvesting.
... The yeast extract was replaced by wine lees in order to reduce fermentation costs, which was possible to reach 59.4 g/L of mannitol for red must and 65.6 g/L for white must in 144 h. The compounds extracted from waste of winemaking are of great importance in several sectors (e.g., food, cosmetics, pharmaceuticals, biofertilizer, and energy [35,[37][38][39]. ...
Article
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Europe is considered the largest producer of wine worldwide, showing a high market potential. Several wastes are generated at the different stages of the wine production process, namely, vine pruning, stalks, and grape marc. Typically, these residues are not used and are commonly discarded. Portugal generates annually approximately 178 thousand metric tons of wine production waste. In this context, the interest in redirecting the use of these residues has increased due to overproduction, great availability, and low costs. The utilization of these lignocellulosic biomasses derived from the wine industry would economically benefit the producers, while mitigating impacts on the environment. These by-products can be submitted to pre-treatments (physical, chemical, and biological) for the separation of different compounds with high industrial interest, reducing the waste of agro-industrial activities and increasing industrial profitability. Particularly, vine-pruning residue, besides being a source of sugar, has high nutritional value and may serve as a source of phenolic compounds. These compounds can be obtained by bioconversion, following a concept of biorefinery. In this framework, the current routes of the valorisation of the pruning residues will be addressed and put into a circular economy context.
... 27 The liquid products, which obtain as a result of pyrolysis of waste polyethylene terephthalates (wPET) made in nitrogen and hydrogen gas environments in a batch reactor, are composed mainly of n-alkane, alkene, single ring aromatic compounds and polyaromatic compounds. 28,29 According to proximate and ultimate analysis, wPETs contain 0.3% moisture, 88.3% volatile matter and 11.4% fixed carbon (wt% daf), and approximately 62% carbon (C), 4% hydrogen (H) and 34% oxygen (O) (wt%). 30,31 C/H ratio has an important effect on transformation of plastics into the liquid and the gas products by thermal methods. ...
Article
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In this study, waste polyethylene terephthalate (wPET) was converted to liquid fuel by the pyrolysis method. It was also investigated both effects of microwave pre‐treatment and catalyst (sodium borohydride) on total conversion and oil+gas yield. The reaction temperature of 375–425°C and the reaction time of 30 min are sufficient for the pyrolysis of waste plastic samples in a batch reactor. In the pyrolysis of wPETs, the highest oil + gas yield of 45% was obtained under the conditions of reaction temperature of 425°C and reaction time of 30 min. The highest total conversion was 62% of microwave pre‐treated wPETs under catalytic conditions. It can be argued that microwave pre‐treatment and NaBH4 influence the oil+gas yield in pyrolysis experiments. According to the gas chromatography–mass spectrometry (GC–MS) analysis results of the oil products, they consist of aromatic, mono and multi‐ring aromatic compounds and polyaromatic compounds. Higher heating values of the solid products obtained in pyrolysis are approximately 4000–6000 cal/g. According to X‐ray diffraction analysis (XRD) of the solid products, they consist largely of crystalline terephthalic acid (C8H6O4). This article is protected by copyright. All rights reserved.
... jp/ en/) with an external heating mechanism for cattle manure, chicken manure, and bamboo, at a carbonization temperature of approximately 400-500 °C for 2 h. A rotary kiln carbonizer (MES50, Kanazawa City, Ishikawa, Meiwa Co. Ltd., Japan) with an internal heating mechanism was used for slaughterhouse wastewater, rice husk, and woodchip carbonization at 400-500 °C for 30 min according to procedures outlined by Ferjani et al. (2019) and Song et al. (2012) (Suppl. Table 5 Additional information). ...
... Moreover, biochars have been valorized for soil remediation and amendment resulting in pollutants immobilization, improvement of soils' water holding capacity and fertility, crops growth and production yields, and decrease of greenhouse gas emissions from soils (Ayaz et al., 2021;Sri Shalini et al., 2020). However, a great limitation of the biochars' reuse in agriculture is their low N contents which are lost by volatilization during the pyrolysis process (El-Bassi et al., 2021;Haddad et al., 2020;Hadroug et al., 2019;Ibn Ferjani et al., 2019;Keskinen et al., 2021). The higher the pyrolysis temperature, the lower is the produced biochar's N content (Hadroug et al., 2021b;Hassan et al., 2020;Ibn Ferjani et al., 2020). ...
Article
During the last decade, biochars have been considered as attractive and eco-friendly materials with various applications including wastewater treatment, energy production and soil amendments. However, the important nitrogen losses during biochars production using the pyrolysis process have limited their potential use in agriculture as biofertilizer. Therefore, it seems necessary to enrich these biochars with nitrogen sources before their use in agricultural soils. This paper is the first comprehensive review on the assessment of biomass type and the biochars' properties effects on N recovery efficiency from aqueous solutions as well as its release and availability for plants when applying the N-enriched chars in soils. In particular, the N recovery efficiency by raw biochars versus the type of the raw feedstock is summarized. Then, correlations between the adsorption performance and the main physico-chemical properties are established. The main mechanisms involved during ammonium (NH4–N) and nitrates (NO3–N) recovery process are thoroughly discussed. A special attention is given to the assessment of the biochars physico-chemical modification impact on their N recovery capacities improvement. After that, the application of these N-enriched biochars in agriculture and their impacts on plants growth as well as methane and nitrous oxide greenhouse gas emissions reduction are also discussed. Finally, the main future development and challenges of biochars enrichment with N from wastewaters and their valorization as biofertilizers for plants growth and greenhouse gas (GHG) emissions reduction are provided. This systematic review is intended to promote the real application of biochars for nutrients recovery from wastewaters and their reuse as eco-friendly fertilizers.
... Up to 20% of the harvested wine grape becomes waste during wine production. Grape marc can be used for compost and substrate in ornamental plants (Madjar et al., 2014a) and vegetables (Carmona et al., 2012), as well as for obtaining biofuel (Xu et al., 2009) and biochar (Ibn Ferjani et al., 2019). The use of vine pruning materials in pyrolysis processes solves several environmental problems, including managing large volumes of waste generated annually and reducing CO2 emissions during uncontrolled waste burning (Nunes et al., 2021). ...
Article
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Plant wastes are often burned, leading to air pollution and significant loss of potential soil nutrients. In order to mitigate these drawbacks, the waste can remain or be added to the soil, but this may increase crop diseases and also greenhouse gas (GHG) emissions (e.g., CO2, CH4, N2O). Pyrolysis of vine waste is a promising and relevant technique, and the obtained biochar can be further used as a soil amender, can enhance soil C sequestration and water holding capacity, reduce GHG emissions and nutrient leaching, increase soil fertility, resulting in agronomic, environmental, and economic benefits. The aim of this study was to characterise vine waste from a physicochemical point of view in order to be used as raw material for producing biochar, which will be applied as soil amender. Plant waste material (grapevine prunings and marc) was received from Pietroasa-Istrita Research Station for Viticulture. The materials were characterised in terms of dry matter, loss on ignition, surface morphology, total carbon and nitrogen, bulk density, water holding capacity, pH, electrical conductivity, and mineral content. The obtained results indicate that grapevine prunings and marc are suitable materials for obtaining biochar.
... Nowadays, the common use of grape pomace can be as fertilizers, heat producers and cattle feed [4,5]. In addition, there is evidence about the use of grape pomace as biofuels and biofertilizers [6]. However, these applications have some limits. ...
Article
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Grape pomace is a winery by-product that is more and more valorized as a source of healthy bioactive molecules such as polyphenols. In addition, it can be used to produce some alcoholic beverages, such as grappa, which is a typical distilled Italian alcoholic product. The spent grape pomace after grappa elaboration is mainly considered a food waste. The aim of this study was to reconsider and valorize red and white pomaces obtained after the production of grappa. The total phenolic content of both samples, as well as the antioxidant activity had a decrease after the distillation; however, it was not significant in the case of red pomace. Regarding the phenolic profile, the behavior during the distillation was different, according to the type of pomace. After the grappa production, catechins and epicatechins were the most significant phenolics in white and red pomace, respectively, demonstrating the remaining bioactivity of this by-product, which could be useful within the food industry.
... Condensation of tiny aromatic amorphous carbon structures results in D structures. These findings are consistent with the results observed for exhausted grape marc char after various thermal treatments [72], see Fig. 9. This behavior can be due to the significant amount of amorphous carbon structures formed during low-temperature pyrolysis [57]. ...
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The aim of this review is to investigate the recent development of kenaf derived biochar and its composites in various engineering and agricultural applications including nanostructure catalysts and polymer composites as kenaf biochar and activated carbon are mainly used as material adsorbents and soil amendments. A systematic review on the effect of process parameters of thermal decomposition, pyrolysis towards the production of desired biochar, therefore, is in crucial needs. Based on existing literature, the properties and production of kenaf biomass and resultant biochar are discussed in this paper. This analysis focuses on the unique characteristics of kenaf crops and the resulting biochar, which has a surprisingly large surface area and increased pore volume, to explain their prospective applications, whether in environmental utilization or engineering applications. Range of optimum surface areas for kenaf biochar are around 800–1000 m2/g where they show high adsorption properties. Whereas, the pore volume of activated carbon usually exceeds 1 cm3/g. Recent developments in engineered kenaf biochar technology and its future directions for research and development are also discussed.
... But, the main problem encounters in industry is the knowledge about the type of tar compounds present in the gas. It is a perquisite before deciding the appropriate technology to remove tar [13][14][15]. Therefore, it is important to know the characteristics of the tar produced from the biomass fuel targeted before installation of any industrial-scale biomass thermo-chemical conversion system [16][17][18][19][20][21]. ...
Article
Biomass is an important carbon neutral energy source which is generated in huge quantity naturally and through various human activities. There are different types of biomasses like agricultural waste, forest residue, industrial waste, municipal solid waste etc. However, in biomass thermal conversion process, tar is an inevitable waste or by-product that has a significant impact on the overall efficiency and economy of the process. The present study aims to investigate the potential of using biomass tar as fuel and compare with the parent biomass. Therefore, pyrolysis of three different biomass materials (bamboo, betelnut shell and rice straw) and their tars are investigated in a Thermogravimetric Analyzer (TGA). Pyrolysis experiments are carried out under N2 atmosphere with four different heating rates of 10, 20, 30 and 40 K/min. Maximum temperature used for the pyrolysis experiments is 900℃. Kinetic analysis is done using three model free methods. Kinetic parameters, thermodynamic parameters and reaction models are evaluated. The activation energy for biomass tar is found to be lower than parent biomass material. The results reveal that the biomass tars have good thermal properties and fuel generation capabilities.
... The biomass feedstock consists of extractive (0-14%), lignin (16%), hemicellulose (20%), and cellulose (>40%) [61][62][63]. Generally, the yields of the produced biofuels are dependent on several factors such as the composition of the nature of the feedstock, the moisture content of biomass feedstocks, reactor design, and operating temperature conditions [64][65][66][67]. In the pyrolysis process, the biomass feedstock can be mixed with other materials to improve the quantity and the quality of the product as shown in Table 3. ...
Article
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The catalytic and thermal decomposition of plastic waste to fuels over low-cost catalysts like zeolite, clay, and bimetallic material is highlighted. In this paper, several relevant studies are examined, specifically the effects of each type of catalyst used on the characteristics and product distribution of the produced products. The type of catalyst plays an important role in the decomposition of plastic waste and the characteristics of the oil yields and quality. In addition, the quality and yield of the oil products depend on several factors such as (i) the operating temperature, (ii) the ratio of plastic waste and catalyst, and (iii) the type of reactor. The development of low-cost catalysts is revisited for designing better and effective materials for plastic solid waste (PSW) conversion to oil/bio-oil products.
... Moreover, the application of biochar as a soil additive has been recognized as an effective and eco-friendly method for the remediation of contaminants [2][3][4] and long-term carbon sequestration [5,6]. Its properties (e.g., polarity and aromaticity) largely determine the key functions of biochar [7,8]. So far, biomass organic components, particularly the proportion of lignin, cellulose and hemi-cellulose, have been regarded as the main factor affecting the thermal conversion, composition and structure of biochar [2,9]. ...
Article
In recent years, researchers have sought ways to efficiently convert biomass wastes into biochars with potential for environmental application. Fe and Al salts are reactive constituents that participate in biochar formation. However, their influences on the properties of biochar and its application on contaminant removal and carbon mitigation remain unknown. In this study, FeCl 3 and AlCl 3 were added to two typical biomass wastes (rice straw and poultry litter) during pyrochar and hydrochar production. The effects of Al (III) and Fe (III) on the molecular characteristics, stability, and adsorption efficiency of biochars for polar and nonpolar contaminants were explored. Results showed that Al (III) and Fe (III) significantly changed the properties of biochar. Al (III) facilitated the carbonization of 250 • C pyrochar, but suppressed that of hydrochar and 450 • C pyrochar. Fe (III) enhanced the formation of aromatic structures of both pyrochar and hydrochar, but reduced the abundance of lignin-and condensed aromatics-like species in their dissolved organic carbon fractions. Furthermore, Fe (III) increased the stability and adsorption efficiency of pyrochar and hydrochar for both polar and nonpolar contaminants. These findings provide new insights into the design of functional biochar from biomass wastes with high stability and adsorption efficiency for organic contaminants.
... This activated carbon has cavities and cracks on their external surfaces. Similar findings were registered by Ibn Ferjani et al. [30], Limousy et al. [18] and Eren et al. [31] for raw marc grapes pyrolyzed at various temperatures and olive stones activated by phosphoric acid and zinc chloride, respectively. ...
Article
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Abstract. In this work, four activated carbons were synthetized from natural olive stone (NOS) wastes using ZnCl2 as an activating agent. These activated carbons (OSAC) were synthetized for a constant mass ratio of ZnCl2: NOS of 2:1, a contact time of 2 h and four different heating temperatures (300, 400, 450 and 500 °C). The physicochemical characterization of these activated carbons by various analyses including N2 adsorption–desorption measurements, surface charge evolution versus pH, Boehm titration, Fourier transform (FTIR) and scanning electron microscopy (SEM) showed that the activated carbon produced at a temperature of 400 °C (OSAC 400 °C) exhibited the best properties. Indeed, it has the highest BET surface area, total pore and micropore volumes with values of 740 m2 ·g −1 , 0.57 cm3 ·g −1 and 0.25 cm3 ·g −1 , respectively. Moreover, it is rich in various acidic and basic functional groups that could react with various common adsorbents. The test of these activated carbons, for the adsorption of a cationic (methylene blue (MB)) and anionic (methyl orange (MO)) dye under various experimental conditions, showed that OSAC 400 °C could be considered as an effective, attractive and promising adsorbent for both the tested dyes. The Langmuir’s adsorption capacities of this adsorbent were assessed to 303.0 and 277.8 mg·g −1 for MB and MO, respectively, which are significantly high compared to other various activated carbons. The retention of the pollutants is mainly chemical including hydrogen bond and electrostatic attraction between the dyes and the activated carbon surface.
... However, compared to lignocellulosic materials, RPM-B appears to be exceptionally rich in nutrients (Table 1). For instance, K and "P" contents in the used RPM-B are, respectively, 3.2 and "5.3", 6.4 and "33.2", and 5.0 and "33.2" times higher than the ones reported for exhausted grape marc [27], wood chips residues [28], and pine sawdust [29]. This an important advantage for its valorization in agriculture as a biofertilizer since it can bring sufficient amounts of these two essential macronutrients for an optimal crop development. ...
Article
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In this study, nutrients release/adsorption from/by raw poultry manure-derived biochar produced at a pyrolysis temperature of 600 °C (RPM-B) was assessed under static and dynamic conditions. Batch sequential leaching experiments of RPM-B for a total contact time of 10 days showed that both phosphorus and potassium were slowly released but with higher amounts compared to various other animal- and lignocellulosic-derived biochars. The cumulated released P and K amounts were assessed to 93.6 and 17.1 mg g−1, which represent about 95% and 43% of their original contents in the RPM-B, respectively. The column combined leaching/adsorption experiments showed that amending an alkaline sandy agricultural soil with two doses of RPM-B (at 5% and 8% w:w) resulted in an efficient retention of NO3-N and NH4-N, and on the contrary, important leached amounts of PO4-P, K+, Mg2+, and Ca2+ but with relatively slow kinetic release rates for a long period. Even after 40 days of dynamic leaching, these latter nutrients continued to be released with kinetic rates lower than 10 mg kg−1 d−1. Thus, compared to synthetic fertilizers, RPM-B valorization as organic amendment for poor semiarid soils could be considered as an attractive, eco-friendly, and sustainable waste recycling option.
... Not only does an alkaline medium provide a suitable environment for the precipitation of potassium-struvite, but it also reduces the need to use basic components during precipitation. Grape marc contains some potassium (Patti et al., 2009;Ferjani et al., 2019), and therefore, should be used as a lignocellulosic material in a process within that framework. Turkey is the world's sixth largest grape producer (4.255.000 ...
Article
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This study investigated the production conditions of a potassium magnesium phosphate fertilizer with vinasse (a by-product of the sugar or ethanol industry) and grape marc (a by-product of the wine-making industry). A mixture of vinasse and grape marc was subjected to pyrolysis under a nitrogen gas atmosphere, and water was used to extract potassium from the end product. Potassium magnesium phosphate (potassium-struvite, KMgPO4.6H2O), a slow-release fertilizer compound, was obtained from the extract with potassium to explore process conditions and product characteristics. Producing fertilizer products from residual materials is of paramount significance for conserving natural resources. The mixture was pyrolyzed, allowing us to remove potassium from the complex matrix of concentrated vinasse to a clear and high alkaline solution. The residual carbon was activated by decomposing (pyrolysis) and treating the residue and then washing it with water. The extract had high alkalinity, suggesting that the potassium in the mixture resulted in carbon activation during biomass pyrolysis. Pyrolysis and treatment can be used to produce activated carbon from vinasse. This study also investigated the solubility of vinasse in water and aqueous solutions. K-struvite with 10.67% K2O was about 2% soluble in water, indicating that the end product was a slow-release fertilizer agent. In conclusion, this process can be used to produce potassium (a slow-release fertilizer) and activated carbon (a by-product) from vinasse for different purposes.
... Traditional management strategies involve landfilling and incineration, which are currently provoked as problematic strategies in regards to the environmental impacts [61]. In this context, several reports have demonstrated the efficiency of valorizing Citrus wastes for the green synthesis of biosorbents [62,63], biofertilizers [64], biofuels [65,66], nanomaterials [67,68], and QDs [69,70]. Agricultural and food waste valorization will provide greater protection to the environment through the elimination of such waste and by mediating the synthesis of valuable products such as QDs. ...
Article
Quantum dots (QDs) are promising nanoscale materials with sizes ranging from 1 to 10 nm, and have exponentially triggered scientific interest worldwide during the past decade. They exhibit size-tunable optical features, zero-dimensional structures, and quantum confinement effects. Moreover, they can be tailored to suit various applications. Phyto-synthesis of fluorescent metal chalcogenide QDs and carbon dots (CDs) is a green, feasible, low-cost, and environmentally safe approach to overcome the limitations of chemical and physical synthesis techniques. Different plant extracts provide several phytochemical constituents with numerous functional moieties for natural capping and stabilization of the synthesized metal chalcogenide QDs and CDs. Therefore, the green synthesis of metal chalcogenide QDs and CDs, their optical and structural properties, and applications such as diagnostics, biosensing, heavy metal detection, and photocatalytic degradation are comprehensively summarized in this review. Furthermore, the biovalorization of agricultural wastes, such as fruit and vegetable peels, is addressed to produce high-value metal chalcogenide QDs and CDs. In addition, the toxicity issues associated with these particles are described for the safe usage of QDs. Challenges that restrict the widespread application of QD particles are discussed along with future perspectives for their commercial, safe, and upscale production.
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Straw mulching is a sustainable practice used to control soil erosion. However, different doses of mulch affect the efficiency of straw conservation. This study presents detailed research on how soil physicochemical properties and the hydrological response react to different types of vineyard soil management (Tilled, Grass, Low Straw, High Straw) and seasons (spring, summer, autumn) under conventional management on Anthrosols in Mediterranean conditions. To assess soil properties, core samples and disturbed samples were taken from the topsoil layer (0–10 cm). To evaluate erosion rates, a rainfall simulation experiment was conducted (58 mm h−1 for 30 min) with 10 replicates per treatment and season (120 in total). The results show higher water-stable aggregates (WSA) and soil organic matter (SOM) and lower bulk density (BD) in the mulch and grass treatment groups compared with the Tilled treatment group. High Straw treatment successfully mitigated runoff, while other treatments had significantly higher runoff that triggered sediment loss (SL) and translocation of P, K, Zn and Ni down the slope. There were 254% and 520% higher K losses with Tilled treatment in autumn compared with Low Straw and Grass treatments, respectively. Statistical analysis showed a strong association between element loss and SL, which indicates an ecological threat in degraded and endangered vineyards. Mulch application and grass cover reduce the vulnerability of vineyards, reduce evaporation, act as insulation against high temperatures, reduce erosion and suppress weed growth. The mulch dosage varies depending on the goals and conditions of the vineyard; thus, lower mulch dosage (2 t/ha) is appropriate when soil conditions are favourable and there is no significant need for moisture retention, while higher mulch dosage is necessary in dry regions to maintain soil moisture during high-temperature periods, as well as in sloped areas subjected to erosion.
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The growing global demand for fish has led to an increase in fish waste (FW) production, necessitating efficient waste management strategies. Pyrolysis is a promising way to convert fish waste into high-value products. To achieve optimal waste mass reduction and gain insights into the pyrolysis process, estimating kinetic parameters is essential. This study investigated the pyrolysis of FW, Sardinella fimbriata, a previously unexplored waste source, using a thermogravimetric analyser. The study determined an average activation energy value of 84–124 kJ/mol using model-free isoconversional methods including Flynn-Wall–Ozawa, Kissinger–Akahira–Sunose, and Starink, whereas pre-exponential factor values were predicted to be between 102 and 1011 s−1. Further analysis using Criado's reduced master-plot approach showed that the experimental curves for pyrolysis coincided with many different theoretical plots for reaction mechanisms, with a concentration on reaction-order models. The analysis of thermodynamic parameters showed positive values of enthalpy change and Gibbs energy change for S. fimbriata FW pyrolysis, suggesting that the process is endothermic and non-spontaneous, while negative values of entropy change were observed across all conversion degrees as a result of the breakdown of complex organic molecules into simpler compounds. This study provides insights into the feasibility of thermal processes and offers new guidance for FW waste management and resource recovery, expanding the understanding of pyrolysis kinetics and thermodynamics for fish waste treatment.
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This article reports the first multistep combination of pulsed electric field (PEF; 3 kV/cm, 100 kJ/kg, 2 Hz, 100 ms) and supercritical fluid extraction (SFE) with CO2 (10–20 MPa, 25 mL/min [10% EtOH], 50 °C, 60 min) for exhausted grape marc (EGM). This current protocol was mainly created to recover bioactive glycosylated and lipidic compounds. In this regard, total antioxidant capacity (TAC) was enhanced up to 68% after PEF treatment compared to conventional soaking. However, re-extracting PEF-treated EGM after the application of SFE (PEF + SFE) boosted the efficiency by up to 87%. Several polyphenols (kaempferol, luteolin, scutellarin, and resveratrol, among others), together with other glycosylated structures, were identified by liquid chromatography coupled with mass spectrometry analysis. The bioactive lipidic compounds extracted by SFE, along with the carbohydrate fraction (free sugars) favourably extracted by PEF pre-treatment (mainly glucose, but also fructose and sucrose), were concurrently detected by nuclear magnetic resonance. The remaining solid fraction after treatment was also characterised. Different microscopic morphology was observed by scanning electron microscopy (SEM) on untreated, PEF, and PEF + SC–CO2–treated EGM. Differential thermogravimetric (DTG) curves determined by thermogravimetric analysis (TGA) also suggested alternative and potential means for the valorisation of this matrix.
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In this work, a valorisation of olive and wine industry co-products (olive pomace and grape marc, respectively) through different thermochemical processes is studied. The characterization of olive pomace and grape marc is made to evaluate which thermochemical process is more suitable for each type of biomass and a specific application. Then, a life cycle assessment (LCA) of olive pomace value chain is made to assess the environmental impacts. Several scenarios of biomass conversion process were considered: combustion, gasification and hydrothermal carbonization (HTC) followed by gasification to generate electricity; and pyrolysis to produce biochar, bio-oil and syngas. Finally, a techno-economic analysis was performed for each mentioned scenario to evaluate the feasibility and conclude which scenario is more economically advantageous. Results suggest that valorisation of olive pomace might be more suitable through the gasification process and grape marc through the pyrolysis process. From the LCA was possible to conclude that combustion scenario has the highest environmental impact. In comparison, gasification, HTC and pyrolysis presented a lower impact with a value of 69.45%, 50.96% and 40.97%, respectively, considering combustion as 100% impact. Regarding the techno-economic analysis, several scenarios have promising results with some scenarios with payback periods inferior to 5 years. The only exception is HTC followed by gasification which in current days is not competitive with other technologies. Overall gasification and pyrolysis are promising alternatives to the valorisation of olive pomace and grape marc. The drying process has an important role in terms of environmental impact and economic viability.
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The current study explored the bioenergy potential of waste miscanthus grass (WMG). The kinetic study of WMG was evaluated via two model-free methods, in a thermogravimetric analyzer (TGA), at dynamic heating rates under an inert ambiance. The pyrolysis was performed in a semi-batch fixed bed reactor at 500 oC, 80 oC min heating rate, and 1 mm particle size. The evolution of hot vapors during pyrolysis was explored using a TGA-FTIR analyzer. Finally, the bio-oil and biochar were characterized by their physicochemical properties. The kinetic results established that WMG followed a multi-step decomposition process, and the average activation energy gained from KAS and ST was found to be 197.66 and 179.64 kJ mol-1, respectively. TGA-FTIR study revealed the foremost release of carbon dioxide (28.22%), followed by a carbonyl (25.40%), and ether (19.12%). Further, the pyrolysis of WMG yielded 29.32 wt. % of bio-oil at the optimized condition whereas, physicochemical results of bio-oil established; 65.16% carbon content, 26.16 MJ kg-1 HHV, 34.15 cP viscosity, and 812 kg m-3 density. GC-MS study of bio-oil confirmed the maximal release of hydrocarbons and phenols. Finally, characterization results of miscanthus grass biochar (MGB) demonstrated an excellent feedstock for industrial and domestic applications.
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The south of Brazil has a high production of peaches which generates the stone as residue. The recycling of biomass and plastic waste is a challenge that must be overcome. Therefore, co-pyrolysis emerges as a possibility for joint conversion of peach stone and plastic bags into value-added products. Thus, the objective is to obtain new products, emphasizing the organic fraction of the bio-oil obtained under the best experimental conditions, and to characterize it by GC-MS. The experiments provided a three-phase bio-oil: two organic phases with different densities and an aqueous phase. It was observed that the central point experiment (temperature at 500 °C and blend composition, % peach stone/polyethylene, 80/20) generated the highest yield of bio-oil. However, the experiment at the lowest temperature and with greater addition of plastic waste produced a higher organic fraction. Using gas chromatography, 161 chemical compounds were identified in the denser organic phase, emphasizing the phenols. In the lighter organic fraction, hydrocarbons were the majority among the 70 compounds identified. The results suggest that the interaction between biomass and polyethylene influences the characteristics of the products obtained, since polyethylene acts as dispersant and as hydrogen donor. Co-pyrolysis, in this research, proves to be efficient and viable, allowing the joint destination of those environmental liabilities.
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Coffee is a relevant agricultural product and one of the most consumed hot beverages globally. To assess the impact of pyrolysis temperatures (400 to 600℃) and heating rates from 5 to 20℃/min on the biochar production yields and textural characteristics, spent coffee grounds was subjected to slow-pyrolysis in a pilot-scale reactor. Further, complementary spectroscopic and textural analyses were executed to evaluate the impacts of pyrolysis temperatures on the corresponding biochar surface properties including textural characteristics, reactivity, and surface functionalities. The correlation of pyrolysis temperature with change in biochar’s surface properties along with CO2 mitigation efficiency is examined. The ultimate analysis, FTIR spectroscopy, ¹³C-NMR spectroscopy and Raman scattering measurements confirmed an increment in the degree of aromaticity or decomposition of organic complexes in biochar. The development of basic surface functionalities after the thermal treatment was ascertained by XPS and NEXAFS analyses. Based on the surface composition and textural properties, the CO2 adsorption capacity of SCG-600 was assessed under varying column temperatures at ambient pressure employing a fixed-bed reactor. In this investigation, SCG-600 showed a large CO2 uptake of 2.8 mmol/g under a typical post-combustion scenario. CO2 adsorption mechanism followed the pseudo-first-order kinetics and lower activation energy over varying investigated temperatures reveals the binding process is physical in nature. SCG-600 could be proposed as promising biochar that possesses a combination of higher surface area, well-developed microporous structure, heterogeneous and basic surface functional moieties to meet the specific requirements in dynamic CO2 adsorption.
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Lignite, as an abundant and low-cost material, was tested for lead (Pb(II)) removal from aqueous solutions under various experimental conditions for both static (batch) and dynamic (column) experiments. Static assays showed that Pb(II) removal efficiency increases with rising in its initial concentration, aqueous pH, and adsorbent dosage values. Adsorption kinetic and isothermal data were well fitted with the pseudo-second-order and Freundlich models, respectively, suggesting that lead removal by lignite is mainly governed by chemical processes and occurs heterogeneously on multilayer surfaces. The maximum Langmuir’s adsorption capacity was equal to 61.4 mg$\cdot $g$^{-1}$, which is high in comparison to various natural materials. The laboratory column experiments showed that Pb(II) breakthrough curves and subsequent lignite adsorption efficiency is highly dependent on the bed height. Due to the short time contact between Pb(II) and lignite particles inside the column, the highest adsorption capacity was about 21%, which is lower than the one found in the batch mode. Even under dynamic conditions, lignite exhibits a high adsorption capacity compared to other adsorbents, which promotes its use as a low-cost and efficient material for Pb(II) and the removal of other heavy metals from wastewaters.
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Hydrothermal carbonization (HTC) and pyrolysis are two promising thermochemical conversion strategies to valorize agricultural wastes, yet neither process can be implemented alone to sustainably upgrade both wet and dry feedstocks. HTC is ideal for wet feedstocks, such as manure, but its solid hydrochars suffer from low surface area and stability. Pyrolysis is well suited to dry agricultural residues, but pyrolysis biochars have low nutrient contents and bio-oils are often highly oxygenated. We propose an integrated process that co-pyrolyzes a nutrient-rich cow manure hydrochar with raw agricultural residues, which effectively reduces the environmental impact of these wastes while producing value-added bioproducts. Biochars produced from the proposed process are more suitable for soil amendments due to their enhancement in bioavailable nutrients and surface area than the manure hydrochars and raw biomass. Co-pyrolysis of blends enriched with cow manure yield oils higher in alkanes and alkenes with fewer oxygenated compounds.
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Valorisation of food waste offers an economical and environmental opportunity, which can reduce the problems of its conventional disposal. Food waste is commonly disposed of in landfills or incinerated, causing many environmental, social, and economic issues. Large amounts of food waste are produced in the food supply chain of agriculture: production, post-harvest, distribution (transport), processing, and consumption. Food waste can be valorised into a range of products, including biofertilisers, bioplastics, biofuels, chemicals, and nutraceuticals. Conversion of food waste into these products can reduce the demand of fossil-derived products, which have historically contributed to large amounts of pollution. The variety of food chain suppliers offers a wide range of feedstocks that can be physically, chemically, or biologically altered to form an array of biofertilisers and soil amendments. Composting and anaerobic digestion are the main large-scale conversion methods used today to valorise food waste products to biofertilisers and soil amendments. However, emerging conversion methods such as dehydration, biochar production, and chemical hydrolysis have promising characteristics, which can be utilised in agriculture as well as for soil remediation. Valorising food waste into biofertilisers and soil amendments has great potential to combat land degradation in agricultural areas. Biofertilisers are rich in nutrients that can reduce the dependability of using conventional mineral fertilisers. Food waste products, unlike mineral fertilisers, can also be used as soil amendments to improve productivity. These characteristics of food wastes assist in the remediation of contaminated soils. This paper reviews the volume of food waste within the food chain and types of food waste feedstocks that can be valorised into various products, including the conversion methods. Unintended consequences of the utilisation of food waste as biofertilisers and soil-amendment products resulting from their relatively low concentrations of trace element nutrients and presence of potentially toxic elements are also evaluated.
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The olive oil industry is an important economic sector in Mediterranean countries. However, oil production is unfortunately accompanied by the generation of huge amounts of olive mill solid wastes (OMSW) and olive mill wastewater (OMWW). In the present study, a strategy is proposed for converting these olive mill wastes into biochar through pyrolysis, for their later use as an organic amendment in agriculture. Specifically, two biochars were prepared from the pyrolysis of OMSW at 500 °C, either alone or impregnated with OMWW (OMSW-B and I-OMSW-B). The characterization of the OMSW and I-OMSW samples and their derived biochars showed that the fixed carbon and ash contents in the feedstocks increased by 38% and 11% respectively for OMSW-B, and by 37% and 12% respectively for I-OMSW-B. Interestingly, the impregnation process significantly increased Na, P, K, Ca and Fe contents in the produced biochars. The effect of OMSW-B and I-OMSW-B amendments at different application dose (1%, 2.5% and 5% wt/wt) on the enzymatic activity of an agricultural soil was performed at laboratory scale with a pot test. The experimental results showed that phosphatase and urease activity increased with biochar application rate; amendment with I-OMSW-B at 1%, 2.5% and 5% enhanced the phosphatase activity by 63%, 142% and 285% and urease activity by 50%, 116% and 149%, respectively. On the other hand, dehydrogenase and protease activities were higher for the application rate of 2.5% biochar. Biochar amendment promoted tomatoes seedling growth after 10 weeks, which was highest in the application rates of 2.5% and 5% for both OMSW-B and I-OSMW-B. Thus, the produced biochars had great potential to be used as biofertilizers in agriculture.
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Despite the huge amounts of grape marc generated in Tunisia from the wine industry, very few efforts have been exerted to manage this harmful waste. Therefore, thermal processes may contribute to an environmental friendly management and also help winemakers to create new economic profitable circuits in an increasingly competitive context. Among the various thermochemical conversion process, pyrolysis is suitable for the recovery of food processing residues, due to their high minerals content and ability to create high added values of the derived products (biochar, bio-oil and syngas). In this context, the aim of this work is to optimize the pyrolysis process in order to benefit from the grape marc potential for achieving highest product yields. Therefore, physico-chemical and energy characteristics of grape marc issued from a Tunisian wine cooperative were determined according to international standards. Thermogravimetric analyzes were also performed to predict the grape marc behavior during degradation under an inert atmosphere. The profile of the mass loss rate shows two decomposition peaks corresponding to the cellulose and lignin decomposition. These peaks are shifted to lower temperatures comparing to several lignocellulosic biomass feedstocks due to high content of minerals that may play a catalytic role in the thermal degradation process. The biochar yield was about 40%, which was never met in literature for agricultural biomass in slow pyrolysis. Such behavior may be attributed to high lignin content in grape marc. Activation energies were calculated using integral Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods and differential Friedman method. The obtained values were 226.8, 224.2 and 229.5 kJ/mol, respectively. Such kinetics data are crucial in the design of the pyrolyzer for Tunisian grape marc recovery.
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Solid char is a product of biomass pyrolysis. It contains a high proportion of carbon, and lower contents of H, O and minerals. This char can have different valorization pathways such as combustion for heat and power, gasification for Syngas production, activation for adsorption applications, or use as a soil amendment. The optimal recovery pathway of the char depends highly on its physical and chemical characteristics. In this study, different chars were prepared from beech wood particles under various pyrolysis operating conditions in an entrained flow reactor (500–1400 °C). Their structural, morphological, surface chemistry properties, as well as their chemical compositions, were determined using different analytical techniques, including elementary analysis, Scanning Electronic Microscopy (SEM) coupled with an energy dispersive X-ray spectrometer (EDX), Fourier Transform Infra-Red spectroscopy (FTIR), and Raman Spectroscopy. The biomass char reactivity was evaluated in air using thermogravimetric analysis (TGA). The yield, chemical composition, surface chemistry, structure, morphology and reactivity of the chars were highly affected by the pyrolysis temperature. In addition, some of these properties related to the char structure and chemical composition were found to be correlated to the char reactivity.
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Biochar produced by pyrolysis of biomass can be used to counter nitrogen (N) pollution. The present study investigated the effects of feedstock and temperature on characteristics of biochars and their adsorption ability for ammonium N (NH4+-N) and nitrate N (NO3--N). Twelve biochars were produced from wheat-straw (W-BC), corn-straw (C-BC) and peanut-shell (P-BC) at pyrolysis temperatures of 400, 500, 600 and 700°C. Biochar physical and chemical properties were determined and the biochars were used for N sorption experiments. The results showed that biochar yield and contents of N, hydrogen and oxygen decreased as pyrolysis temperature increased from 400°C to 700°C, whereas contents of ash, pH and carbon increased with greater pyrolysis temperature. All biochars could sorb substantial amounts of NH4+-N, and the sorption characteristics were well fitted to the Freundlich isotherm model. The ability of biochars to adsorb NH4+-N followed: C-BC>P-BC>W-BC, and the adsorption amount decreased with higher pyrolysis temperature. The ability of C-BC to sorb NH4+-N was the highest because it had the largest cation exchange capacity (CEC) among all biochars (e.g., C-BC400 with a CEC of 38.3 cmol kg-1 adsorbed 2.3 mg NH4+-N g-1 in solutions with 50 mg NH4+ L-1). Compared with NH4+-N, none of NO3--N was adsorbed to biochars at different NO3- concentrations. Instead, some NO3--N was even released from the biochar materials. We conclude that biochars can be used under conditions where NH4+-N (or NH3) pollution is a concern, but further research is needed in terms of applying biochars to reduce NO3--N pollution.
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Activated carbon was produced from banana empty fruit bunch (BEFB) and Delonix regia fruit pod (DRFP) through single step chemical activation process. As both the lignocellulosic wastes showed maximum weight loss at temperatures lower than 500°C, they were carbonized at 450°C (BEFP) and 400°C (DRFP) respectively after impregnating with H 3 PO 4 and KOH. Highest yield of 41.09% was recorded in DRFP treated with H3PO4 followed by other treatments. The KOH treated DRFP recorded maximum bulk density of 0.46 g/ml followed by H 3 PO 4 treated DRFP. The BEFP carbons displayed lower attrition values than DRFP carbons. While the H 3 PO 4 treated DRFP carbon sample showed higher surface area, the untreated DRFP registered higher pore volume. However BET surface area was comparatively low in both the substrates. FT-IR analysis of H 3 PO 4 , KOH and untreated carbon sample, though did not show much difference in surface functional groups, showed shifts in bands and changes in wave numbers and absorbance between the untreated and treated samples indicating chemical transformations during pyrolysis. While highest iodine removal was observed in KOH treated BEFP and DRFP samples, methylene blue reduction was high in H 3 PO 4 , KOH and untreated BEFP carbon samples.
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The application of bio-char (charcoal or biomass-derived black carbon (C)) to soil is proposed as a novel approach to establish a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. Apart from positive effects in both reducing emissions and increasing the sequestration of greenhouse gases, the production of bio-char and its application to soil will deliver immediate benefits through improved soil fertility and increased crop production. Conversion of biomass C to bio-char C leads to sequestration of about 50% of the initial C compared to the low amounts retained after burning (3%) and biological decomposition (∘C common for pyrolysis). Existing slash-and-burn systems cause significant degradation of soil and release of greenhouse gases and opportunies may exist to enhance this system by conversion to slash-and-char systems. Our global analysis revealed that up to 12% of the total anthropogenic C emissions by land use change (0.21 Pg C) can be off-set annually in soil, if slash-and-burn is replaced by slash-and-char. Agricultural and forestry wastes such as forest residues, mill residues, field crop residues, or urban wastes add a conservatively estimated 0.16 Pg C yr−1. Biofuel production using modern biomass can produce a bio-char by-product through pyrolysis which results in 30.6 kg C sequestration for each GJ of energy produced. Using published projections of the use of renewable fuels in the year 2100, bio-char sequestration could amount to 5.5–9.5 Pg C yr−1 if this demand for energy was met through pyrolysis, which would exceed current emissions from fossil fuels (5.4 Pg C yr−1). Bio-char soil management systems can deliver tradable C emissions reduction, and C sequestered is easily accountable, and verifiable.
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Grape stalk is an organic waste produced in great amounts in the industrialization processes of grape. This work presents the results of studies carried out to use this waste as raw material to prepare activated carbon through the physical and chemical route. The physicochemical characterization of this material suggests the presence of unusually high levels of ashes. Metal content was determined and high levels of potassium, sodium, iron, calcium and magnesium in carbonized and raw grape stalk were exhibited. This characteristic made difficult physical activation at high temperatures. A leaching step was included before the activation with steam, and adsorbents with surface areas between 700 and 900 m(2)/g were obtained. Physical activation was also performed at lower temperatures using carbonized grape stalk without leaching, leading to the development of some grade of porosity, with an area of 412 m(2)/g. These results would indicate the catalytic effect of the minerals present in this raw material. Chemical activation using phosphoric acid as activating agent seemed to be a very efficient method as final products with BET areas between 1000 and 1500 m(2)/g were obtained.
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The composting of winery waste is an alternative to the traditional disposal of residues, and also involves a commitment to reducing the production of waste products. We studied two residues (sludge and grape stalks), mixed in two proportions (1:1 and 1:2 sludge and grape stalks (v/v)), and we also examined the effects of grinding the grape stalks. Our results showed that composting the assayed materials was possible. Best results were obtained in the compost heap in which the residues were mixed in the proportion 1:2, and where the grape stalks had been previously ground. Optimum results required a moisture around 55% and a maximum temperature around 65 degrees C and an oxygen concentration not lower than 5-10%. The resulting compost had a high agronomic value and is particularly suitable for the soils of the vineyards which have a very low organic matter content. The compost can be reintroduced into the production system, thereby closing the residual material cycle.
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Biomass is increasingly being recognized as a promising carrier for both heat, energy and chemicals production. However, several aspects still require intense research activity towards a better design and optimization of industrial combustors, gasifiers and pyrolyzer. The objective of this work is to update the CRECK kinetic mechanism of biomass pyrolysis, allowing a better prediction of both yield and composition of the solid residue (biochar). Moreover, further model modifications allow to better describe the variability of hemicellulose in different biomass. To this end, a large set of literature experimental data is collected and organized into a database, which is used to further tune and validate the proposed kinetic mechanism. Although the kinetic model maintains the previous agreement in respect of the rate of biomass pyrolysis, formation and distribution of gas and tar products, the novelty of this work is the greater attention to the predictions of biochar yield and composition, in a wide range of operative conditions. The model describes the solid residue as a mixture of pure carbon together with lumped metaplastic compounds, which represent the whole range of oxygenated and hydrogenated groups bonded to the carbonaceous matrix. These metaplastic species are released to the gas phase with their own kinetics and describe the change of both mass loss and elemental composition of the biochar. These comprehensive predictions of biochar composition are crucial for an accurate description of the successive oxidation and gasification processes.
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This investigation has established a complete environmentally friendly strategy for the valorization of olive mill wastewater (OMW). This valorization process includes different steps, namely, OMW impregnation on sawdust, drying, biofertilizer production, and soil amendment. The OMW impregnation on raw cypress sawdust (RCS) was performed using batch procedure mode. During this impregnation, 59% and 71% of the chemical oxygen demand and total dissolved salts of OMW were adsorbed on RCS. The drying of the impregnated sawdust (IS) and OMW was realized in a convective dryer at temperature ranging between 40 and 60 °C and air velocity ranging between 0.7 and 1.3 m/s. Comparison between both samples demonstrated clearly that the impregnation procedure accelerated the drying process and consequently allowed an ecologic recovery of water from OMW that could be reused. The IS sample was pyrolyzed at 500 °C for green fuel (bio-oil, gas) and char production. This residual char (IS-Char) exhibited higher mass fraction of 34.5%. The IS char characterization showed the presence of important nutrients (potassium, nitrogen, and phosphorus) contents. The application of the IS char as a biofertilizer for rye-grass growth studies under controlled conditions showed promising results in terms of leaf dimensions and mass yields of the plant. These preliminary results indicated the validity of the established strategy to convert OMW from a pollutant to green fuels, agricultural water source, and biofertilizer.
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The goal of the present research is to study the effect of the inorganic species on the pyrolysis mechanism of lignocellulosic biomass. Many contradictions as the catalytic role of inorganic salts characterize the research works published up to now. These ambiguities are reasonably due to the morphological and structural modifications of the reacting biomass by the various demineralization and impregnation methods, that impact on the pyrolysis mechanism. In order to clarify the effect of inorganics on the pyrolysis mechanism, alkali and alkaline earth (AAEM) containing salts were deposited by impregnation method on cypress sawdust. Nuclear magnetic resonance analyses showed that the biomass structure was preserved and that metal deposition passes through a cationic exchange mechanism.
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The influence of pyrolysis conditions on the structure properties and chemical composition of biomass chars was examined. The Raman spectroscopy ID/IG and IV/ID parameters were found to be correlated for pyrolysis temperatures higher than 600 °C. Furthermore, a correlation between IV/ID and the atomic ratio (O+H)/C was identified. These findings would corroborate the assumption that the large carbonaceous structures having defects (D band) would probably form from the condensation of the small amorphous ones (V region). The condensation of these small structures into larger ones would be accompanied by the release of H and O atoms into the gas phase.
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In this work, winery industry wastes were valorised through the extraction of high added value compounds (polyphenols), followed by thermal conversion of the exhausted solid residues. For this purpose, three different temperatures (623, 723 and 823 K) were tested. The increase of the heat treatment temperature resulted in a significant increment in gas production containing methane and other hydrocarbons. Lipophilic liquid product quantity in grape marc was limited both before and after the polyphenol extraction. The recovery of phenolic compounds before the thermal treatment notably decreases the chemical oxygen demand level of the resulting hydrophilic liquid fraction. The pyrolysis residue represents from 30 to 55% of the initial mass but corresponds to a relevant decrease of its volume, and can be considered a good source of graphitic carbon with higher calorific value with respect to the initial grape waste and applicable for energy production.
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Biochar produced during the thermochemical decomposition of biomass not only reduces the amount of carbon emitted into the atmosphere, but it is also an environment-friendly replacement for activated carbon and other carbon materials. In this review paper, researches on biochar are discussed in terms of production method and application. Different processes for biochar production, such as pyrolysis, gasification, hydrothermal carbonization, etc., are compared. Physical and chemical activation methods used to improve the physicochemical properties of biochar and their effects are also compared. Various environmental application fields of biochar including adsorption (for water pollutants and for air pollutants), catalysis (for syngas upgrading, for biodiesel production, and for air pollutant treatment), and soil conditioning are discussed. Recent research trend of biochar in other applications, such as fuel cell, supercapacitor, and hydrogen storage, is also reviewed.
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In Tunisia, seasonal and centralized discharges of tomato waste and grape marc generated from agri-food industries have negative effects on the environment. Characterization of these residues shows that their calorific values are suitable for their energy recovery. However, the high mineral contents and the low bulk densities limit their direct use as biofuel. Therefore, a blending process using sawdust followed by densification into pellets is proposed for the recovery of these agri-food residues. Such strategy allows the pellets to meet standard requirements of the biofuels market. Furthermore, the performance of the pellets is evaluated during combustion tests in domestic boiler. The combustion parameters, the gaseous and particulate matter emissions are analyzed. Results indicate that the pellets prepared from agri-food residues have boiler and combustion efficiencies comparable to wood pellets. However, gaseous and particulate emissions are strongly affected by the operating parameters of the domestic boilers. Therefore, these parameters such as mass flow of water in the heat exchanger, combustible mass flow, primary and secondary inlet air flow should be adapted to each agri-food residue to benefit from these resources without leading to negative environmental impacts.
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Vineyard waste and wastewater generated from wineries present significant risks to the environment if untreated. In this study, we carried out anaerobic co-digestion of grape marc and winery wastewater for energy production in the form of methane and material recovery. The results showed that milling the grape marc prior to being suspended in winery wastewater and inoculated with activated sludge in a 15 weeks batch digestion resulted in the production of 5.04 MJ/kg VS of energy compared with 0.97 MJ/kg VS from the non-milled treatment. Milling of grape marc also showed reduced CO 2 emission, 4.95 l/kg VS compared with 9.96 l/kg VS from non-milled samples. The results suggest that physical pre-treatment of grape marc results in bioenergy production which is comparable to many other organic waste streams such as cattle slurry, hen litter and food processing waste offering significant potential for utilisation by the winery industry.
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Mediterranean countries generate large amounts of olive oil byproducts mainly OMWW (olive mill wastewater) and EOSW (exhausted olive solid waste). Although solid residues have various valorization strategies, there is no economically viable solution for the OMWW disposal. This study aims to recover the OMWW organic contents through solid biofuels production. Hence sawdust and EOSW were used for the OMWW impregnation. The potential of the obtained samples, namely: IS (impregnated sawdust) and IEOSW (impregnated exhausted olive solid waste) were evaluated. Therefore, the physicochemical characterizations and thermogravimetric analyses of the samples were first performed. Secondly, the samples densification into pellets and their combustion in a domestic combustor were carried out. Combustion efficiencies, gaseous and PM (particulate matter) emissions as well as ash contents were evaluated. The analysis finding shows that addition of OMWW leads to an increase of energy content through the heating values increase. An increase of the impregnated samples reactivity was observed and assigned to the potassium catalytic effect. Combustion performances show that the OMWW addition has not a negative effect on their firing quality. Moreover, a beneficial effect on the pollutant emissions is observed with IEOSW pellets. The developed strategy constitutes a promising issue for the OMWW disposal and recovery.
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To compensate for the shortcomings of manure biochar, an ignocellulose-based feedstock (rice straw) was added into manure-based feedstock (swine manure) at 3:1, 1:1 and 1:3 (w/w) manure/straw ratios during biochar production within the pyrolysis temperature ranging from 300-700 ˚C. The results showed that the pyrolysis temperatures and the proportions of straw added both influenced the biochar properties. The overall properties of biochars at 300 ˚C, 400 ˚C and 500 ˚C were thoroughly different from those at 600 ˚C and 700 ˚C by principal components analysis (PCA). The XRD, FTIR and SEM spectra suggested that the addition of straw considerably changed the mineral crystals, functional groups and porous structures in manure biochar, respectively. The Zn(Ⅱ) adsorption batch experiments showed that the biochars with more proportions of manure had the largest Zn(Ⅱ) adsorption capacity than other biochars at 300 ˚C, which was attributed to the mineral components, oxygen functional groups and surface areas. To meet varied agronomic and environmental requirements, the different conditions including pyrolysis temperatures and proportions of straw added should be quantitated.
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This paper aims to analyse energy related properties, thermal degradation behaviour and devolatilization kinetics of five Cameroonian biomasses namely, Palm Kernel Shells (PKS), Mesocarp Fibres (PMF), Coffee Husk (CH), Corn Cob (CC) and Peanut Shell (PNS). The thermal degradation was performed using thermogravimetric analysis (TG). Different behaviours related to the presence of chemical constituents such as cellulose, hemicellulose and lignin were obtained. Comparison of the thermal characterization shows that PMF is the most interesting feedstock with the highest heating values and reactivity due to higher volatile content. Decomposition of TG data was analysed by applying diffusion and chemical reaction kinetic models. Obtained results show that biomass pyrolysis is represented by two successive steps. The devolatilization stage characterized by high weight loss rate is well described by diffusion reaction models. In contrast, the char formation stage characterized by low weight loss rate is well described by third order chemical reaction models.