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Paracetamol and Ibuprofen Removal from Aqueous Phase Using a Ceramic-Derived Activated Carbon
Abstract
Emerging pollutants, including pharmaceuticals and personal care products, have been detected in surface and groundwaters. The adsorption of paracetamol and ibuprofen, two widespread drugs, has been studied in aqueous medium, using a ceramic-derived carbon (CeDC) and a commercial activated carbon (CoAC). CeDC yielded a BET surface area of 895 m 2 g −1 , a bimodal pore size distribution (13.2 and 35 nm) and a total pore volume of 1.99 cm 3 g −1. CoAC had an approximate surface area of 1000 m 2 g −1 , a homogeneous pore size distribution and a total pore volume of 0.42 cm 3 g −1. Kinetic and equilibrium tests were carried out in batch systems to study the materials' sorption performances. The intraparticle diffusion model best fitted the experimental kinetic data. The maximum ibuprofen sorption capacities were 120 mg g −1 and 133 mg g −1 for CoAC and CeDC, respectively, whereas no major differences on the maximum paracetamol sorption capacities (qm) were observed among the sorbents (150-159 mg g −1). Therefore, CeDC, synthesized easily from a ceramic composite, improved time and sorption capacity of paracetamol and ibuprofen compared to the commercial activated carbon, indicating the potential of the developed carbon as an emerging pollutant sorbent material.
... In recent studies, agro-waste materials have emerged as promising precursors for the production of activated carbons used for the removal of ibuprofen from aqueous solutions (Bursztyn Fuentes et al. 2022;Sandoval-González et al. 2022). Various agro-waste materials, such as Lantana camara stalk (Ganesan et al. 2021), olive waste cake (Baccar et al. 2012), cork (Mestre et al. 2009), olive stones (Mansouri et al. 2015), coconut shell (Arinkoola et al. 2022;Bursztyn Fuentes et al. 2022), and cocoa husk (Bello et al. 2020b;Villabona-Ortíza et al. 2021) have been investigated as precursors for the synthesis of activated carbons. ...
... In recent studies, agro-waste materials have emerged as promising precursors for the production of activated carbons used for the removal of ibuprofen from aqueous solutions (Bursztyn Fuentes et al. 2022;Sandoval-González et al. 2022). Various agro-waste materials, such as Lantana camara stalk (Ganesan et al. 2021), olive waste cake (Baccar et al. 2012), cork (Mestre et al. 2009), olive stones (Mansouri et al. 2015), coconut shell (Arinkoola et al. 2022;Bursztyn Fuentes et al. 2022), and cocoa husk (Bello et al. 2020b;Villabona-Ortíza et al. 2021) have been investigated as precursors for the synthesis of activated carbons. Table 1 provides examples of these activated carbon materials and their respective sources. ...
... Chemical oxidation of activated carbon can introduce oxygen-containing functional groups, such as carbonyl or carboxyl, lactonic, phenolic, and hydroxyl groups, positively impacting ibuprofen adsorption (Guedidi et al. 2013). Various oxidizing agents, including phosphoric acid (Álvarez-Torrellas et al. 2016;Bello et al. 2020a;Bursztyn Fuentes et al. 2022), sulfuric acid (Al-Kindi and Al-Haidri 2021), and potassium carbonate (Al-Kindi and Al-Haidri 2021), as well as activating agents like zinc chloride (Villabona-Ortíza et al. 2021), have been employed for the oxidative post-treatment of activated carbon to enhance its adsorptive removal of ibuprofen. For example, the oxidation treatment of activated carbon in hydrogen peroxide with/without ultrasonic irradiation slightly increases its adsorption capacity. ...
The presence of pharmaceuticals in ecosystems is a major health issue, calling for advanced methods to clean wastewater before effluents reach rivers. Here, we review advanced adsorption methods to remove ibuprofen, with a focus on ibuprofen occurrence and toxicity, adsorbents, kinetics, and adsorption isotherms. Adsorbents include carbon- and silica-based materials, metal–organic frameworks, clays, polymers, and bioadsorbents. Carbon-based adsorbents allow the highest adsorption of ibuprofen, from 10.8 to 408 mg/g for activated carbon and 2.5–1033 mg/g for biochar. Metal–organic frameworks appear promising due to their high surface areas and tunable properties and morphology. 95% of published reports reveal that adsorption kinetics follow the pseudo-second-order model, indicating that the adsorption is predominantly governed by chemical adsorption. 70% of published reports disclose that the Langmuir model describes the adsorption isotherm, suggesting that adsorption involves monolayer adsorption.
... 2.34 mg/g in 90 min was obtained from rice husk [112], 7.23 mg/g from mango seeds in 64 min [113], 28.09 mg/g from orange peel in 40 min [87], and 50 mg/g in 60 min from coffee grounds biomaterial [1]. Additionally, the maximum adsorption capacity obtained using commercial activated carbon was 221 mg/g in 72 h [70], and 150 mg/g in 24 h [114]. From this finding, SDAC is considered a highly effective adsorbent which can give a high removal percentage to purify water. ...
Pharmaceutical pollution in water is a critical environmental issue. This study investigates the removal of paracetamol (PCM) from water using activated carbon derived from Sesbania wood, a fast-spreading plant with promising structural properties for activated carbon. The batch adsorption results demonstrated the effectiveness of Sesbania-derived activated carbon (SDAC) in removing PCM solution, achieving a removal efficiency of 89%. In fixed-bed adsorption, a removal efficiency of 87.6% was attained within 210 min while treating 1050 ml of solution. The Redlich-Peterson model was employed as the best adsorption isotherm, with a maximum adsorption capacity (qmax) of 70.68 mg/g. Kinetics analysis favours the pseudo-second-order model. Thermodynamic results suggest an exothermic and spontaneous adsorption mechanism. The decision tree machine learning (ML) model outperformed the gradient boosting (R² = 0.88), random forest models (R² = 0.88), and the artificial neural network model (R² = 0.75) in predicting PCM removal using the adsorbent. Sensitivity analysis using Shapley additive (SHAP) revealed that adsorbent mass is the most influential parameter in PCM removal. This study presented a novel application of activated carbon derived from the Sesbania plant, highlighting its high efficiency in PCM removal through experimental analysis and ML-based optimization.
... This is a significant advantage if the application of the adsorption mechanism of this AC11 is performed with the inorganic ion composition of soft surface waters rather than the controlled ion conditions of laboratory DIW. Finally, AC11 from this study exhibits outstanding capacity to adsorb IBU compared to AC produced from other biomasses, e.g., Nauclea diderrichii waste (70.92 mg⋅g − 1 [79]), Lantana camara stalk (106.4 mg⋅g − 1 [80]), coconut shell (89.29 mg⋅g − 1 , [81]; recycled textiles (53.9 mg⋅g − 1 [44]) or commercial granular ACs (185.2 mg⋅g − 1 [82], 120 mg⋅g − 1 [83]). ...
... As no data are available on the adsorption of ketorolac on carbonaceous materials, the reported adsorption capacities for similar compounds are given for comparison. The maximum ibuprofen adsorption capacity was 120 mg g −1 for ceramic-derived carbons [56]. Etodolac adsorption capacity of 20 mg g −1 was determined for activated biochar from the mixture of apricot and peach stones and almond shells [57]. ...
The development of efficient adsorbents for sustainable adsorption processes is required in environmental studies. Here, we propose using carbonized Ailanthus altissima leaves as a novel adsorbent, derived from invasive species that threaten biodiversity. Biochar was prepared by pyrolysis at 500 °C, activated with ZnCl2 and tested for the target adsorbates—active pharmaceutical ingredients (APIs). A range of characterization techniques were employed—FTIR, SEM, XPS and Raman spectroscopy—and the adsorption of representative APIs was analyzed. The adsorption kinetics revealed that the adsorbent reached equilibrium within a 3 h period. The adsorption capacities for the selected model substances ranged from 59 mg g⁻¹ for atenolol to 112 mg g⁻¹ for paracetamol, while the highest values were recorded for ketorolac and tetracycline at over 130 mg g⁻¹. The excellent retention is ascribed to the developed surface area, the availability of oxygen surface functional groups and the aromatization of the biochar. The proposed biochar, which is obtained in a sustainable process, proves to be a highly efficient adsorbent for selected pharmaceuticals.
... 86 On the other hand, some researchers used similar pH conditions but higher sample volume and longer reaction time, which allowed for room and longer interactions between analytes and adsorbents. 87,88 However, a lower capacity obtained by Hamoudi and colleagues suggests that increased mass of adsorbent and longer reaction time did not have much influence on the adsorption capacities. 89 The adsorption capacities for CAF ranged between 76.3−102 mg/g, which were lower than those reported in the literature (Table 7). ...
Plastic waste poses a serious environmental risk, but it can be recycled to produce a variety of nanomaterials for water treatment. In this study, poly(ethylene terephthalate) (PET) waste and acid mine drainage were used in the preparation of magnetic mesoporous carbon (MMC) nanocomposites for the adsorptive removal of pharmaceuticals and personal care products (PPCPs) from water samples. The latter were then characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), and ζ potential. The results of Brunauer–Emmett–Teller isotherms revealed high specific surface areas of 404, 664, and 936 m²/g with corresponding pore sizes 2.51, 2.28, and 2.26 nm for MMC, MMAC-25%, and MMAC-50% adsorbents, respectively. Under optimized conditions, the equilibrium studies were best described by the Langmuir and Freundlich models and kinetics by the pseudo-second-order model. The maximum adsorption capacity for monolayer adsorption from the Langmuir model was 112, 102, and 106 mg/g for acetaminophen, caffeine, and carbamazepine, respectively. The composites could be reused for up to six cycles without losing their adsorption efficiency. Furthermore, prepared adsorbents were used to remove acetaminophen, caffeine, and carbamazepine from wastewater samples, and up to a 95% removal efficiency was attained.
... It is noted that the material carries positive charges when pH < pHpzc and negative charges when pH > pHpzc [20]. In addition, acetaminophen (pKa = 9.5) and caffeine (pK a = 14.0) were in neutral form [21,22] as the natural pH of each solution was lower than their respective pKa (pH acetaminophen = 6.01 and pH caffeine = 5.90). Thus, electrostatic interactions did not rule out the adsorption of acetaminophen and caffeine by BT-CO 2 and HT-CO 2 . ...
This study explored the adsorption of acetaminophen and caffeine using CO2-activated biochar (BT-CO2) and hydrochar (HT-CO2) derived from Tingui shell biomass. The experimental data from kinetic and equilibrium adsorption tests were employed in batch and fixed-bed systems. In the batch system, a specific amount of the adsorbent was added to a known volume of the solution, and the mixture was agitated for a set period to allow adsorption to occur. In the fixed-bed system, the solution was passed through a column packed with the adsorbent, allowing for continuous adsorption. These systems pave the way for future research. The findings revealed that HT-CO2 exhibited a greater surface area and a higher presence of oxygen-containing functional groups than BT-CO2. These functional oxygen groups had a notable impact on the adsorption capacity of the adsorbents for pharmaceutical substances. In the batch systems, BT-CO2 demonstrated a maximum adsorption capacity of 221.4 mg g−1 for acetaminophen and 162.7 mg g−1 for caffeine, while HT-CO2 exhibited higher capacities of 383.2 mg g−1 for acetaminophen and 189.7 mg g−1 for caffeine. In the fixed bed configuration, HT-CO2 displayed a maximum adsorption capacity of 82.2 mg g−1 for acetaminophen and 45.60 mg g−1 for caffeine. The predominant mechanisms involved in the removal of acetaminophen and caffeine were identified as H-bonding and π-π bonds. These results underscore the promising potential of these carbons as effective adsorbents for treating water contaminated with pharmaceutical residues, inspiring further exploration in this field and offering hope for the future of water treatment by providing a solid foundation for future research and development.
... The effectiveness of activated carbon for adsorbing different pharmaceuticals and personal care products (PPCPs) (Bursztyn Fuentes et al. 2022;El Naga et al. 2019;García-Rosero et al. 2022;Kim et al. 2022) and other emerging pollutants (Ahn et Moreno-Marenco et al. 2020) have been documented. The adsorption generally occurs via porefilling/size exclusion, hydrogen bonding, π-π electro-donor acceptor, electrostatic interactions, and hydrophobic interaction mechanism (Ahn et Liu et al. 2022a;Pamphile et al. 2019). ...
Access to drinkable water is becoming more and more challenging due to worldwide pollution and the cost of water treatments. Water and wastewater treatment by adsorption on solid materials is usually cheap and effective in removing contaminants, yet classical adsorbents are not sustainable because they are derived from fossil fuels, and they can induce secondary pollution. Therefore, biological sorbents made of modern biomass are increasingly studied as promising alternatives. Indeed, such biosorbents utilize biological waste that would otherwise pollute water systems, and they promote the circular economy. Here we review biosorbents, magnetic sorbents, and other cost-effective sorbents with emphasis on preparation methods, adsorbents types, adsorption mechanisms, and regeneration of spent adsorbents. Biosorbents are prepared from a wide range of materials, including wood, bacteria, algae, herbaceous materials, agricultural waste, and animal waste. Commonly removed contaminants comprise dyes, heavy metals, radionuclides, pharmaceuticals, and personal care products. Preparation methods include coprecipitation, thermal decomposition, microwave irradiation, chemical reduction, micro-emulsion, and arc discharge. Adsorbents can be classified into activated carbon, biochar, lignocellulosic waste, clays, zeolites, peat, and humic soils. We detail adsorption isotherms and kinetics. Regeneration methods comprise thermal and chemical regeneration and supercritical fluid desorption. We also discuss exhausted adsorbent management and disposal. We found that agro-waste biosorbents can remove up to 68–100% of dyes, while wooden, herbaceous, bacterial, and marine-based biosorbents can remove up to 55–99% of heavy metals. Animal waste-based biosorbents can remove 1–99% of heavy metals. The average removal efficiency of modified biosorbents is around 90–95%, but some treatments, such as cross-linked beads, may negatively affect their efficiency.
... The regenerated PA as a percentage of desorption was found to be 63.2% after six cycles as elucidated in Figure 12. Commercial AC [19] 101 Olive stones AC [20] 100 Tea waste AC [21] 99.42 Brazil nutshells AC [22] 306.7 Butia capitata endocarp AC [23] 100.60 plant sludge of the beverage industry AC [24] 145 Ceramic AC [25] 159 Cannabis sativum Hemp AC [26] 16.18 Fruit of Butiacapitate AC [27] 98.19 Oak cupule AC (present study) 97.91 ...
This inquiry used ultrasonic waves to uptake paracetamol (PA) by using oak-based activated carbon (ACO). The surface of ACO was explored based on FT-IR, SEM, and XRD before and after the adsorption. The kinetic data for PA adsorption onto ACO corresponds to a pseudo-second-order kinetic model. Isothermal models of the Langmuir, Freundlich, D-R, and Temkin were used. The adsorption of PA onto ACO was found to be a monolayer with 96.03% uptake, which corresponds to Langmuir. The thermodynamic experiments revealed the endothermic nature of PA adsorption onto ACO. Under the investigated optimal conditions, the adsorption capacity of PA onto ACO was found to be 97.1 mg. L-1. ACO could be recycled after six regenerations. Ultimately, sonicating has adequate performance for the uptake of PA by ACO.
Ibuprofen, abbreviated to IBP, is a widely used non-steroidal anti-inflammatory drug that can find its way into the environment via hospital and medical wastes, municipal wastewater, and through veterinary usage. IBP is harmful to aquatic life with long lasting effects and as such its release can pose an environmental hazard. Therefore, this study focussed on determining the potential of modified biochar derived from a by-product of the food industry, namely grass jelly tree waste, as an effective adsorbent for removing IBP from aqueous solutions. The modified biochar could be prepared by pyrolysis at 700 °C for 1 hour, then phosphoric acid modification was achieved by soaking for 24 hours, followed by washing with water until neutral. This modified biochar exhibited a specific surface area (SSA) of 111 m²/g, a total pore volume of 0.097 cm³/g with an average pore diameter of 3.49 nm. Adsorption parameters such as contact time, solution pH, concentration and temperature were studied. Batch adsorption experiments indicate that the modified biochar is highly efficient in removing IBP, with equilibrium rapidly being reached after 2 hours. Kinetic studies demonstrated that the adsorption of IBP on modified biochar fitted better to the pseudo-second order kinetic model than the pseudo-first order model. The Sips isotherm model which is a combination of Langmuir and Freundlich models demonstrated a superior fit of adsorption behaviour with the maximum adsorption capacity for IBP being 200.73 mg/g at optimal pH (pH 2). The thermodynamic parameters show that the adsorption is spontaneous, exothermic, and results in increased disorder. Thus, the use of grass jelly tree waste in the production of biochar can be a sustainable and economical approach for converting this industrial waste into a useful adsorbent for the remediation of pharmaceutical contaminated water.
The widespread use of pharmaceuticals and the disposal of unused portions into the environment expose the aquatic ecosystem to large volumes of waste. In this study, a green adsorbent, magnetic-sulfated cellulose-supported biocomposite (MSCB), was produced from cannabis biomass, a carbohydrate-based source. The prepared MSCB was characterized in detail using various techniques (ATR-FTIR, FE-SEM, STEM, EDX, XRD, BET, VSM, TGA, and pHpzc) and used as an adsorbent to remove paracetamol (PCM) from wastewater. The adsorption studies examined factors such as adsorbent amount (12.5–100 mg), pH (2–10), initial concentration (20–100 mg/L), contact time (1–420 min.), temperature (25–45 °C), matrix environment influence, and reusability. Characterization results confirmed that the synthesized MSCB was successfully sulfated, exhibited a porous structure, possessed a high magnetization value, and demonstrated thermal stability. XRD analysis also verified that the material was cellulose-supported. The best adsorption conditions were found to be a 25 mg adsorbent amount, pH of 4, an initial concentration of 80 ppm, and a contact time of 300 min. Moreover, the results revealed that the adsorption of PCM onto MSCB aligned more closely with the pseudo-second-order kinetic model and the Langmuir isotherm model. The maximum theoretical adsorption capacity was calculated to be 126.6 mg/g at 25 °C. Furthermore, it was noted that even in a dense matrix medium, MSCB maintained its removal efficiency, and after five applications, its reusability remained fairly strong. It was concluded that the green MSCB could be a highly effective adsorbent for removing PCM from wastewater.
Graphical Abstract
Thermochemical treatment of empty fruit bunches (EFBs) had been proven to be the fastest way of converting this agro-industrial waste into value. Two-step carbonization and activation was used to convert the EFB to activated carbon with high specific surface area (SSA) and porosity. Hydrothermal carbonization was done at 225 to 275 °C; at retention time of 1–3 h. Activation was done at 800 °C for 1 h, using KOH at two different concentrations. The BET surface area, porosity and surface functional groups of the activated carbon were investigated. The samples experienced change in colourations, with the degree of colouration increases with the time and temperature of the reaction. The increase in these parameters also led to increase in the alkane functional groups and corresponding decreased in the hydroxyl functional groups. The specific surface area was measured using BET and maximum surface of 1375.26 m²/g was obtained when the biomass was carbonized at 275 °C for 1 h, and activated at 800 °C using KOH at a concentration of 1:1 to the hydrochar. Ultrasonic post-treatment of the activated carbon enhanced the BET surface area and pore volume to about 1.13 and 1.16 times, respectively. The corresponding pore diameter and volume at this optimum condition were 3.32 nm and 0.73 cm³/g, respectively. The material demonstrated a high specific surface area for electronic and ionic diffusions.
Paracetamol, a common pain reliever, has seen a significant rise in use, particularly during the Coronavirus Disease 2019 (COVID-19) pandemic. This widespread consumption has led to increased levels of paracetamol in the environment through wastewater discharge. This raises concerns about its potential impact on aquatic ecosystems. Here, we review the state-of-the-art methods for removing paracetamol from wastewater, focusing on adsorption techniques. We explore how different materials and operational conditions influence the effectiveness of this approach. We also discuss the potential of combining adsorption with oxidative methods for enhanced removal. We further assess the environmental impact by critically examining the ecotoxicological effects of paracetamol on aquatic organisms. This analysis compares established toxicity values with those observed in studies using real wastewater samples. Finally, we highlight the specific needs for further research and development of efficient and sustainable strategies to mitigate paracetamol pollution, ensuring the safety of both human and aquatic life.
The escalating use of pharmaceuticals, particularly analgesic and antipyretic drugs, due to the rise of emerging ailments has led to a significant environmental concern, that is, increased presence of paracetamol in various water sources. This surge is predominantly linked to heightened paracetamol consumption by individuals seeking relief from COVID-19 symptoms. Consequently, the contamination poses health risk to those consuming affected water, primarily due to the production of toxic compound such as 4-aminophenol, known for its liver damaging effects. This review addresses the surging production and consumption of paracetamol to mitigate water contamination. Essential measures for efficient paracetamol removal from water sources are emphasized. The wastewater is the most affected by paracetamol, with a high concentration compared to the other sources. A few other contemporary treatment methods are covered, with an emphasis on the adsorption process. Adsorption is one of the predominant approaches that has been extensively researched and applied to treat pharmaceutical pollutants, with a high removal percentage reaching 98% by using activated carbon as an adsorbent. The use of efficient adsorbents that have previously been employed for paracetamol elimination will be discussed. The paper also provides a concise interpretation of the mechanisms involved in paracetamol adsorption, presenting an innovative perspective on the efficacy of this process as an excellent method for removal.
The removal of caffeine (CFN) and acetaminophen (ACT) from water using low-cost activated carbons prepared from artichoke leaves (AAC) and pomegranate peels (PAC) was reported in this paper. These activated carbons were characterized using various analytical techniques. The results showed that AAC and PAC had surface areas of 1203 and 1095 m2 g−1, respectively. The prepared adsorbents were tested for the adsorption of these pharmaceuticals in single and binary solutions. These experiments were performed under different operating conditions to evaluate the adsorption properties of these adsorbents to remove CFN and ACT. AAC and PAC showed maximum adsorption capacities of 290.86 and 258.98 mg g−1 for CFN removal, 281.18 and 154.99 mg g−1 for the ACT removal over a wide pH range. The experimental equilibrium adsorption data fitted to the Langmuir model and the kinetic data were correlated with the pseudo-second order model. AAC showed the best adsorption capacities for the removal of these pharmaceuticals in single systems and, consequently, it was tested for the simultaneous removal of these pollutants in binary solutions. The simultaneous adsorption of these compounds on AAC was improved using the central composite design and response surface methodology. The results indicated an antagonistic effect of CFN on the ACT adsorption. AAC regeneration was also analyzed and discussed. A statistical physics model was applied to describe the adsorption orientation of the tested pollutants on both activated carbon samples. It was concluded that AAC is a promising adsorbent for the removal of emerging pollutants due to its low cost and reusability properties.
Pharmaceuticals are emerging contaminants that have physiological effects on aquatic life even in trace amounts. Paracetamol (PCT) (also known as acetaminophen) is one of the most used analgesics and antipyretics for the treatment of fever and pain. Its detection in different water bodies has raised a concern around the globe, necessitating a need for its efficient removal from water. Over the last few years, researchers have synthesized and employed a wide range of materials for adsorptive remediation of PCT. In this review, for the first time, we critically reviewed the role of such materials in PCT removal along with the effect of different uptake parameters, the thermodynamics, and the removal mechanism. Special emphasis has been placed on providing a plausible mechanism for the uptake of paracetamol in terms of macroscopic, empirical modeling, spectroscopic, density functional theory (DFT), and artificial neural network (ANN) analysis. The key mechanism of PCT uptake involves hydrogen bond formation, van der Waals forces, n-π, π-π, and electrostatic interactions. In many of the reported studies, pseudo-second-order kinetics and Langmuir isotherm models were commonly fitted to PCT uptake data. The testing of such adsorbents in real wastewater and their regeneration has been specially discussed. A comparative overview of a wider range of adsorbents revealed that carbonaceous and agriculturally derived materials have promising performance. Finally, this review reports useful findings, challenges, and prospects for better efficiency of the adsorbents, and it will be beneficial for researchers interested in the development of novel adsorbents for the removal of PCT from real environmental and industrial water.
Keywords: Paracetamol; Emerging contaminants; Acetaminophen; Adsorption; Wastewater; Adsorbent; Water pollution; Density functional theory; Artificial neural network.
Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently used pharmaceuticals for human therapy, pet therapeutics, and veterinary feeds, enabling them to enter into water sources such as wastewater, soil and sediment, and seawater. The control of NSAIDs has led to the advent of the novel materials for treatment techniques. Herein, we review the occurrence, impact and toxicity of NSAIDs against aquatic microorganisms, plants and humans. Typical NSAIDs, e.g., ibuprofen, ketoprofen, diclofenac, naproxen and aspirin were detected at high concentrations in wastewater up to 2,747,000 ng L-1. NSAIDs in water could cause genotoxicity, endocrine disruption, locomotive disorders, body deformations, organs damage, and photosynthetic corruption. Considering treatment methods, among adsorbents for removal of NSAIDs from water, metal-organic frameworks (10.7-638 mg g-1) and advanced porous carbons (7.4-400 mg g-1) were the most robust. Therefore, these carbon-based adsorbents showed promise in efficiency for the treatment of NSAIDs.
The presence of emerging contaminants in the environment, such as pharmaceuticals, is a growing global concern. The excessive use of medication globally, together with the recalcitrance of pharmaceuticals in traditional wastewater treatment systems, has caused these compounds to present a severe environmental problem. In recent years, the increase in their availability, access and use of drugs has caused concentrations in water bodies to rise substantially. Considered as emerging contaminants, pharmaceuticals represent a challenge in the field of environmental remediation; therefore, alternative add-on systems for traditional wastewater treatment plants are continuously being developed to mitigate their impact and reduce their effects on the environment and human health. In this review, we describe the current status and impact of pharmaceutical compounds as emerging contaminants, focusing on their presence in water bodies, and analyzing the development of bioremediation systems, especially mycoremediation, for the removal of these pharmaceutical compounds with a special focus on fungal technologies.
In the present research, the effect of two hybrid treatments, ozone followed by powdered activated carbon (PAC) or PAC followed by ozone (O3), was studied for the removal of two drugs present in water: diclofenac and carbamazepine. In the study, two initial concentrations of each of the contaminants, 0.7 mg L1 and 1.8 mg L1, were used. Different doses of PAC between 4–20 mg L1 were studied as variables, as well as different doses of O3 between 0.056–0.280 mg L1. The evolution of the concentration of each contaminant over time was evaluated. From the results obtained, it was concluded that the combined treatment with ozone followed by PAC reduces between 50% and 75% the time required to achieve 90% removal of diclofenac when compared with the time required when only activated carbon was used. In the case of carbamazepine, the time required was 97% less. For carbamazepine, to achieve reduction percentages of up to 90%, O3 treatment followed by PAC acted faster than PAC followed by O3. In the case of diclofenac, PAC treatment followed by O3 was faster to reach concentrations of up to 90%. However, to reach yields below 80%, O3 treatment followed by PAC was more efficient.
On October 2020, Sestili and Fimognari reported that acetaminophen (N-aetyl-para-aminophenol), commonly known as paracetamol, induces or worsens glutathione (GSH) consumption in elderly patients affected by early or mild COVID-19
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Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 ο C to 700 ο C led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY ⁻ and increased electrostatic repulsion between anionic SPY ⁻ and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water.
Graphic Abstract
Assessing the adsorption properties of nanoporous materials and determining their structural characterization is critical for progressing the use of such materials for many applications, including gas storage. Gas adsorption can be used for this characterization because it assesses a broad range of pore sizes, from micropore to mesopore. In the past 20 years, key developments have been achieved both in the knowledge of the adsorption and phase behavior of fluids in ordered nanoporous materials and in the creation and advancement of state-of-the-art approaches based on statistical mechanics, such as molecular simulation and density functional theory. Together with high-resolution experimental procedures for the adsorption of subcritical and supercritical fluids, this has led to significant advances in physical adsorption textural characterization. In this short, selective review paper, we discuss a few important and central features of the underlying adsorption mechanisms of fluids in a variety of nanoporous materials with well-defined pore structure. The significance of these features for advancing physical adsorption characterization and gas storage applications is also discussed.
With the advent of better detection, more micro-contaminants are being found in water. Many of thesemicro-contaminants come from medical therapies and personal care products. These chemicals are comprisedof a wide-range of substances including pharmaceuticals, dietary supplements, veterinary drugs,fragrances, hair care products, body lotions, oral care, and cosmetics. Many of these products enhanceour quality of life and in some cases, provide life-saving therapies. But, they come with an environmentalcost. Scientific research has found sub-therapeutic levels of many of these chemicals in our waterwaysand in our finished drinking water, causing concern about the potential environmental and public healthimpacts associated with very low, chronic exposure. As tailored therapies and personal care productsare developed, it is crucial to consider how to control emerging contaminants from medical therapiesand personal care products. Specific actions and policies can be implemented now by adopting upstreamapproaches to prevent waste and decrease environmental exposures.
The overwhelming population growth in recent decades and water crisis along with limited and uneven geographical distribution of fresh water resources is a growing challenge for the economic and human development. Wastewater reclamation and use could be an alternative for intact water sources and a promising solution to water scarcity and unequal distribution. However, wastewater is a double-edged resource both as an accessible water source for food production and human usage and concurrently may carry uncharacterized content with unknown toxicological profile causing acute or long-term health risks. Pharmaceuticals, cosmeceuticals, nanomaterials and their chemical decomposition derivatives found in wastewater are not well known in many cases. Their unknown toxicity, teratogenicity and carcinogenicity profile associated with lack of monitoring and control measures impose a significant hazard risk on the public health. This paper reviews the evidence on the health risks associated with the wastewater use for irrigated food production and the imposed risk on the end consumers mainly from pharmaceutical industry and related research facilities. Then, we suggest an applied framework for planning and policy-making to mitigate the health risks and optimally employ reclaimed wastewater for human purposes.
Gas adsorption is an important tool for the characterisation of porous solids and fine powders. Major advances in recent years have made it necessary to update the 1985 IUPAC manual on Reporting Physisorption Data for Gas/Solid Systems. The aims of the present document are to clarify and standardise the presentation, nomenclature and methodology associated with the application of physisorption for surface area assessment and pore size analysis and to draw attention to remaining problems in the interpretation of physisorption data.
Activated carbon of dende coconut mesocarp was used to investigate the removal of paracetamol from water by adsorption. The results indicated that the retention of paracetamol was favored in activated carbon with neutral surface properties. The textural features and presence of a transport pores network contributed to ensuring the accessibility to the inner porosity, and the microporosity must be large enough to accommodate the paracetamol molecule. Chemisorption and mainly physisorption are important in the paracetamol removal. Pseudo-second order equation and Langmuir model were chosen to best present the experimental data. The adsorption process was non-spontaneous and endothermic with increase in system disorder.
We present a two-step methodology for the preparation of highly activated carbons with tailored morphologies and micropore size distributions (MPSD) through the hydrothermal carbonization (HTC) of renewable biomass – sucrose – and further activation. Depending on the activation agent, activated carbons with spherical (K2CO3 or steam activation) or sponge-like morphologies (KOH activation) were obtained. The control of the activation variables allows tailoring the MPSD of the materials, with K2CO3 activation at 700 – 800 ºC originating porous materials with molecular sieve properties and KOH activation giving porous carbon materials with wider MPSD. The highly developed porous structures of the activated carbons give them remarkable adsorption capacities for the removal of pharmaceutical compounds of distinct therapeutical classes (i.e. ibuprofen, paracetamol, clofibric acid, caffeine and iopamidol). While the superactivated carbon obtained by KOH activation at 800 ºC has very high adsorption capacities for all the pharmaceutical compounds assayed the material obtained by K2CO3 activation at 800 ºC has similar adsorption capacity for all pharmaceuticals but iopamidol, the most voluminous compounds. The distinct performance of the porous carbons materials for the removal of the pharmaceutical compounds is mainly related to their MPSD. The high performance of some of the synthetized carbons allied to the possibility of controlling the size of the particles in the HTC step allows envisaging their use as filter media but also coupled to other advanced water treatment technologies (e.g. membrane systems). Moreover, the above mentioned properties associated with the acidic surface chemistry of the developed activated carbons opens new possibilities for the synthesis of functional carbon-based materials.
The adsorption of bentazon onto Lawsonia inermis wood-based activated carbon (LWAC) was carried out in this work. The effects of different reaction parameters such as the initial bentazon concentration, contact time, activated carbon dosage, stirring rate, temperature and pH on bentazon adsorption were investigated in a batch process mode. Equilibrium data were analyzed by the Langmuir, Freundlich and Temkin isotherm model. Langmuir isotherm provided the best fit to the equilibrium data with maximum adsorption capacity of 169.49mg/g at 20°C. Adsorption kinetic was found to follow the pseudo-second-order kinetic model. The mechanism of the adsorption process was determined from the intraparticle diffusion model. The calculated thermodynamic parameters such as ΔG°, ΔH° and ΔS° showed that the adsorption of bentazon onto LWAC was feasible, spontaneous and exothermic at 20–40°C. Desorption of the used LWAC was studied using ethanol as solvent and a percent desorption efficiency of bentazon equalizes 73.8% was obtained after three cycles.
This study aims to investigate the performance of an activated carbon cloth for adsorption of ibuprofen. The cloth was oxidized by a NaOCl solution (0.13 mol L-1) or thermally treated under N2 (700°C for 1hour). The raw and modified cloths were characterized by N2 adsorption-desorption measurement at 77 K, CO2 adsorption at 273 K, Boehm titrations, pHPZC measurements, X-ray Photoelectron Spectroscopy analysis, and by infrared spectroscopy. The NaOCl treatment increases the acidic sites, mostly creating phenol and carboxylic groups and decreases both the specific surface area and slightly the micropore volume. However, the thermal treatment at 700°C under N2 induced a slight increase in the BET specific surface area and yielded to the only increase in the carbonyl groups content. Ibuprofen adsorption studies of kinetics and isotherms were carried out at pH = 3 and 7. The adsorption properties were correlated to the cloth porous textures, surface chemistry and pH conditions. The isotherms of adsorption were better reproduced by Langmuir-Freundlich models at 298, 313 and 328 K. The adsorption of ibuprofen on the studied activated carbon cloths at pH 3 was an endothermic process. The pore size distributions of all studied ibuprofen-loaded fabrics were determined by DFT method to investigate the accessible porosity of the adsorbate. Both treatments do not influence the kind of micropores where the adsorption of ibuprofen occurred.
The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.
Concern about environmental protection has increased over the years from a global viewpoint. To date, the prevalence of adsorption separation in the environmental chemistry remains an aesthetic attention and consideration abroad the nations, owning to its low initial cost, simplicity of design, ease of operation, insensitivity to toxic substances and complete removal of pollutants even from dilute solutions. With the renaissance of isotherms modeling, there has been a steadily growing interest in this research field. Confirming the assertion, this paper presents a state of art review of adsorption isotherms modeling, its fundamental characteristics and mathematical derivations. Moreover, the key advance of the error functions, its utilization principles together with the comparisons of linearized and non-linearized isotherm models have been highlighted and discussed. Conclusively, the expanding of the nonlinear isotherms represents a potentially viable and powerful tool, leading to the superior improvement in the area of adsorption science.
A SiO2-C composite (SC) was prepared via sol-gel method using industrial raw materials: commercial partially hydrolysed tetraethyl orthosilicate as an ethoxylated silica precursor (ESP) and phenolic-formaldehyde resin as a carbon precursor. The synthesized composite, constituted by a silica network cross-linked with a carbon network, resulted in a material with a sharp pore size distribution (pore size diameter ~ 32 nm) and a high specific surface area (~350 m²/g). In a subsequent step, it was possible to isolate each network: Carbon (C) and Silica (S). In this work, the composite synthesis, and the isolation paths to obtain the individual structures are described. In addition, the composite and the isolated structures were mineralogically and structurally characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (laser of 785 nm = 1.58 eV) (RS), nuclear magnetic resonance (NMR) and thermogravimetric analyses (TGA). The textural characterization was performed by nitrogen adsorption (SBET), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM-EDS). The three materials exhibited properties suitable for applications such as catalysis, immobilization of bioactive molecules and dyes, drug delivery, among others. In particular, the carbonaceous network had a pseudo graphene structure and microdomains of high activity, which would enhance its use as a low-cost material in new green technologies for wastewater treatment and drinking water purification.
Rising medical needs have intensified the release of pharmaceuticals and their residues in the environment. Pharmaceuticals were reported in aquatic water bodies of 71 countries. Pharmaceuticals were commonly detected in ng/L to μg/L concentration ranges. However, manufacturing industry units release pharmaceuticals in their effluents in up to mg/L concentration levels. Pharmaceutical's universal presence causes both environmental toxicity and human health concerns. The inability of wastewater treatment plants to completely remove pharmaceuticals raises more concerns. Therefore, aqueous pharmaceutical removal technologies are becoming necessary. Biochar based low-cost technologies are gaining attention as an alternative for activated carbon in water and wastewater treatment. Pharmaceutical sorption onto biochar shows enormous potential due to its surface porosity and functionality. Pharmaceutical sorption mechanisms including H-bondings, π-π electron donor acceptor and pore diffusions are discussed. Comparative evaluation of different biochars for pharmaceutical removal is provided.
Environmental (pH, temperature ionic strength, cations, anions) and process (pyrolysis temperature, particle size, adsorbent dosage, initial concentration) parameters were evaluated for ciprofloxacin and acetaminophen sorption onto a series of sustainable banana peel biochars. Ciprofloxacin and acetaminophen were chosen as model pharmaceuticals for removal owing to their worldwide presence in aquatic systems. After pyrolytic preparation from 450 to 750 °C, the biochars were qualitatively and quantitatively characterized by physicochemical, morphological, mineralogical and elemental analyses. Batch sorption studies were employed to evaluate the pH effects from 2 to 10, biochar pyrolysis temperatures (450, 550, 650, and 750⁰C), particle sizes (30-50, 50-100, 100-150 BSS mesh), adsorbent dosages (0.5, 1.0, 2.0 g/L), adsorbate concentrations (0.5-200 ppm) and uptake temperatures (10, 25, 40 °C) on sorption efficiency. Maximum pharmaceutical sorption is achieved by the biochar prepared at 750 °C. Sorption rate increased with decreasing in biochar particle size from 30-50 to 100-150 BSS mesh. Relationships between biochar properties and their sorptive potential showed positive correlations with surface area, total pore volume, %C, %ash and C/N molar ratios. Sorption data was modelled using different isotherm models and both kinetic and thermodynamic equations. Maximum Langmuir capacities of ciprofloxacin and acetaminophen on BPBC750 were 23.3 and 57.3 mg/g at 10 and 45 °C, respectively. Langmuir isotherm fittings and thermodynamic parameters confirmed the exothermic sorption (for ciprofloxacin) and endothermic sorption (for acetaminophen). The role of ionic strength, cations and anions on pharmaceuticals sorption were evaluated. H-bonding, π-π-interactions and pore diffusion were major contributors to pharmaceutical sorption.
Laboratory investigations show that rates of adsorption of persistent organic compounds on granular carbon are quite low. Intraparticle diffusion of solute appears to control the rate of uptake, thus the rate is partially a function of the pore size distribution of the adsorbent, of the molecular size and configuration of the solute, and of the relative electrokinetic properties of adsorbate and adsorbent. Systemic factors such as temperature and pH will influence the rates of adsorption; rates increase with increasing temperature and decrease with increasing pH. The effect of initial concentration of solute is of considerable significance, the rate of uptake being a linear function of the square-root of concentration within the range of experimentation. Relative reaction rates also vary reciprocally with the square of the diameter of individual carbon particle for a given weight of carbon. Based on the findings of the research, fluidized-bed operation is suggested as an efficient means of using adsorption for treatment of waters and waste waters.
This study investigated the removal of Acetaminophen (ACT) using biochars having different physicochemical characteristics. Biochars subjected to post-pyrolysis heat-treatment at 300°C for different treatment times (0, 3.5, 8 and 24 h) were used. The resulting biochars were characterized using FTIR and X-ray diffraction spectroscopy. Experiments for ACT adsorption with different biochars loads (0.0, 0.05, 1, and 2 g L⁻¹) were performed. Using the best performing material, ACT adsorption was investigated for additional biochar loads (4.0, and 6.0 g L⁻¹) and experiments to test the effect of ionic strength were undertaken for different ions (chloride, carbonate, and nitrate) at three different concentrations (0.0, 1.0, 5.0 mM). The results showed that the changes to the surface of the thermally treated biochars increased the adsorption of ACT. The changes in the amount of oxygen-containing functional groups on the surface of the modified biochars (e.g., C=O from 47.8 a.u. to 152 a.u. in the untreated and thermally treated biochars, respectively), as well as modifications to their crystalline structure are considered to be the reason for the observed improvement. Adsorption isotherm and kinetic models suggest the generation of an adsorbate monolayer and chemisorption as the rate-limiting step. The different anions tested were found to have a significant influence on ACT adsorption, related to their electronegativity and steric effect, as confirmed by the multivariate analysis.
Biochar was obtained from Eucalyptus pruning residues with a non-conventional device named Kon-Tiki kiln. The average heat of combustion of the biochar, 27.3 MJ kg −1 , was higher than that of Eucalyptus wood, 17.8 MJ kg −1. Activation with CO 2 was performed by varying the activation time from 0 to 60 minutes. The activated carbons (ACs) and the carbon precursor have been characterised and tested for paracetamol removal in the liquid phase, studied in both kinetic and equilibrium aspects. ACs presented an increase in BET area (up to 845 m 2 /g), total pore volume and microporosity with the activation time. The pseudo-second order model was the one that best fitted the experimental data. Elimination of paracetamol was much faster when using ACs, 5 h, than when using the biochar, 3 days. However, pollutant removal was greater than 95 % for all materials, which is a promising result for low-cost biochars in a difficult economic context. All the adsorption equilibrium experiments exhibited multilayer behaviour, showing values up to 98 mg g −1 for the maximum monolayer-ad-sorption capacity.
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Discarded bamboo culms of Guadua chacoensis were used for biochar remediation of aqueous As(V). Raw biochar (BC), activated biochar (BCA), raw Fe3O4 nanoparticle-covered biochar (BC-Fe), and activated biochar covered with Fe3O4 nanoparticles (BCA-Fe) were prepared, characterized and tested for As(V) aqueous adsorption. The goal is to develop an economic, viable, and sustainable adsorbent to provide safe arsenic-free water. Adsorbents were characterized using scanning electron microscopy (SEM) and energy dispersive analysis by X-ray (SEM-EDX), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (TEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), Brunauer-Emmett-Teller surface area measurements (SBET), point of zero charge determinations (PZC), and elemental analysis. Activation with KOH increased the O/C ratio and the surface area of BC from 6.7 m2/g to 1239.7 m2/g (BCA). As(V) sorption equilibrium was achieved within <2 h for all four adsorbents and kinetics followed the pseudo-second-order model. At a 10 mg/L initial As(V) concentration, BC-Fe achieved a 100% removal (5 mg/g) over a pH 5 to 9 window. Sorption was endothermic on all four adsorbents and the capacities rose with the increasing temperature. Langmuir capacities at 40 °C for BC, BCA, BC-Fe, and BCA-Fe were 256, 217, 457, and 868 mg/g, respectively, and capacities were compared with other sorbents. Breakthrough fixed-bed column sorption was carried out for BC and BC-Fe producing 6.6 mg/g and 13.9 mg/g bed capacities, respectively. Potassium phosphate was a better As stripping agent than sodium bicarbonate. Performance of the adsorbents in an As(V)-spiked natural water and a naturally As(V)-contaminated domestic water were assessed. Robust arsenate sequestration occurred generating As-safe water (As <0.01 mg/L), despite the presence of competing ions. Stoichiometric precipitation of iron-arsenate complexes triggered by iron dissolution was also established.
A super activated carbon (SAC) was produced by KOH-activation of a biomass waste for paracetamol (PCT) adsorption from aqueous solution and for adsorption-thermal regeneration cycles. The SAC and the regenerated SAC after five adsorption-regeneration cycles (RSAC-5th) were fully characterized by several techniques. The N 2 physisorption showed that the S BET values of the SAC and RSAC-5th are remarkably different, being 2794 m² g ⁻¹ and 889 m² g ⁻¹ , respectively. The XPS analysis demonstrated that the SAC surface is composed by oxygen containing-groups, whilst the RSAC-5th also presents nitrogen ones, provenient from the PCT molecules. The adsorption studies revealed that the maximum adsorption capacity (Q m ) for the SAC (356.22 mg g ⁻¹ ) is higher than that for RSAC-5th (113.69 mg g ⁻¹ ). Also, the results demonstrated that the PCT adsorption is governed by both physisorption and chemisorption and the ab initio calculations showed the chemisorption mainly occurs in carboxylic groups.
In this work chili seeds (Capsicum annuum) were used as raw material in the synthesis of biochar at temperatures between 400 and 600 °C. The samples were chemically, texturally and morphologically characterized and their properties were correlated with the calcination temperature. The adsorption mechanism of IBP was elucidated by analyzing the effect of solution pH, ionic strength and temperature, whereas that, the intraparticle diffusion mechanism was clarified through the application of a 3D diffusional model. The results evidenced that raising the pyrolysis temperature promotes a greater content of disordered graphitic carbon (51.6–85.02%) with small surface area (0.52–0.18 m2/g) and low quantity of functional groups. The adsorption study demonstrated that the biochar synthesized at 600 °C (C600) enhances the adsorption capacity >50 folds compared with chili seeds. Moreover, at pH = 7 the adsorption mechanism is governed by π-acceptor and attractive electrostatic interactions, whereas at basic pH the main adsorption mechanism is π-acceptor. Additionally, hydrophobic interactions become important by increasing the presence of NaCl. The application of 3D diffusional model based on surface diffusion interpreted clearly the kinetic curves obtaining values of Ds ranging from 2.31 × 10−8–2.51 × 10−8 cm2 s−1. Besides, it was determined that intraparticle mass flux is larger along the shortest axis of the seed, and always directed toward the particle center. The maximum mass flux takes place in the center of particle, and it advances like a moving front as time was increased.
The remediation of paracetamol (PA), an emerging contaminant frequently found in wastewater treatment plants, has been studied in the low concentration range (0.3–10 mg L−1) using as adsorbent a biomass-derived activated carbon. PA uptake of up to 100 mg g−1 over the activated carbon has been obtained, with the adsorption isotherms being fairly explained by the Langmuir model. The application of Reichemberg and the Vermeulen equations to the batch kinetics experiments allowed estimating homogeneous and heterogeneous diffusion coefficients, reflecting the dependence of diffusion with the surface coverage of PA. A series of rapid small-scale column tests were carried out to determine the breakthrough curves under different operational conditions (temperature, PA concentration, flow rate, bed length). The suitability of the proposed adsorbent for the remediation of PA in fixed-bed adsorption was proven by the high PA adsorption capacity along with the fast adsorption and the reduced height of the mass transfer zone of the columns. We have demonstrated that, thanks to the use of the heterogeneous diffusion coefficient, the proposed mathematical approach for the numerical solution to the mass balance of the column provides a reliable description of the breakthrough profiles and the design parameters, being much more accurate than models based in the classical linear driving force.
A commercial microporous–mesoporous granular activated carbon was modified by oxidation with either H2O2 in the presence or absence of ultrasonic irradiation, or NaOCl or by a thermal treatment under nitrogen flow. Raw and modified materials were characterized by N2 adsorption–desorption measurements at 77 K, Boehm titrations, pH measurements and X-ray photoelectron spectroscopy. Ibuprofen adsorption kinetic and isotherm studies were carried out at pH 3 and 7 on raw and modified materials. The thermodynamic parameters of adsorption were calculated from the isotherms obtained at 298, 313 and 328 K. The pore size distribution of carbon loaded with ibuprofen brought out that adsorption occurred preferentially into the ultramicropores. The adsorption of ibuprofen on pristine activated carbon was found endothermic, spontaneous (ΔG° = −1.1 kJ mol−1), and promoted at acidic pH through dispersive interactions. All explored oxidative treatments led mainly to the formation of carbonyl groups and in a less extent to lactonic and carboxylic groups. This then helped to enhance the adsorption uptake while decreasing adsorption Gibbs energy (notably −7.3 kJ mol−1 after sonication in H2O2). The decrease of the adsorption capacity after bleaching was attributed to the presence of phenolic groups.
Cu(II) adsorption by the biochars prepared from three crop straws at 400°C was investigated under acidic conditions. The adsorption increased with increase in pH, i.e. pH from 3.5 to 6.0. The adsorption capacity followed the order: peanut straw char>soybean straw char>canola straw char, while the desorption of pre-adsorbed Cu(II) had a reverse trend. The more negative surface charge on biochars from canola straw led to more electrostatic adsorption of Cu(II) compared to the other two biochars. Fourier transform mid-infrared photoacoustic spectroscopy data revealed that adsorption of Cu(II) caused an apparent shift of the vibrational bands assigned to the carboxyl and phenolic hydroxyl groups along with less negative zeta potential of the biochars that adsorbed Cu(II), which suggested that the Cu(II) was adsorbed specifically through the formation of surface complexes. The Langmuir equation was used to predict adsorption capacity of Cu(II) by the biochars, with maximum predicted adsorption in the ranges 0.58–1.40 and 0.48–0.79mol/kg at pH 5.0 and 4.5, respectively. The adsorption of Cu(II) by these biochars was greater than that by a commercial activated carbon in the pH ranged from 3.5 to 5.0 with a maximum adsorption of 0.18mol/kg at pH 5.0.
The purpose of the present work was to synthesize a novel mesoporous activated carbon from an invasive weed to investigate its potential application for removal of the emerging organic contaminants in waters. The worldwide highly consumable non-steroidal anti-inflammatory drug (NSAID); ibuprofen (Ibu), was chosen for the study due to its toxicity and global occurrence in waters. Keeping this in mind, Artemisia vulgaris (common name: Mugwort) leaves were processed by physical and chemical activation to obtain the mesoporous honeycomb-structured activated carbon (MAC) to mitigate Ibu. To understand the activity of the activated carbon towards contaminant, adsorption batch mode process was investigated for the solid–liquid phase characteristics of Ibu–water system. Both kinetic and equilibrium models were evaluated over a wide range of conditions to determine the rate laws and maximum Ibu uptake capacity. A decisive reliance of adsorption capacity on pH was observed in pH range from 2 to 9. The high surface area (358.20m2/g), mesoporosity (2.46nm) and surface functionality of MAC played significant role in Ibu uptake. Plausible mechanistic findings for adsorptive mitigation were substantiated by spectroscopic techniques viz. SEM, FTIR, EDX and ζ potentiometry.
Multiple steps in the Boehm titration are carried out in a variety of manners by different research groups, thereby making results difficult to compare. The methods standardized in this paper include method of agitation, use of dilute titrant, carbon removal from reaction bases and the effect of air on NaOH standardization; uncertainty estimations are also shown. By examining the multiple agitation methods, it was found shaking was the optimal method for use in the Boehm titration as other methods (stirring and sonicating) affect the carbon surface. It was also found that filtering the carbon and reaction base mixture did not affect the titration, nor did the use of dilute titrant. Solutions must be freshly standardized prior to use since storage (even over a one week time period) results in a change in concentration.
Hospital wastewaters contain a variety of toxic or persistent substances such as pharmaceuticals, radionuclides, solvents and disinfectants for medical purposes in a wide range of concentrations due to laboratory and research activities or medicine excretion. Most of these compounds belong to the so called emerging contaminants; quite often unregulated pollutants which may be candidates for future regulation depending on research on their potential health effects and monitoring of their occurrence. Their main characteristic is that they do not need to persist in the environment to cause negative effects since their high transformation/removal rates can be compensated for by their continuous introduction into the environment.Some of these compounds, most of them pharmaceuticals and personal care products may also be present in urban wastewaters. Their concentrations in the effluents may vary from ng L−1 to μg L−1.In this paper, hospital effluents and urban wastewaters are compared in terms of quali–quantitative characteristics. On the basis of an in-depth survey: (i) hospital average specific daily water consumptions (L patient−1 day−1) are evaluated and compared to urban ones (L person−1 day−1), (ii) conventional parameters concentrations in hospital effluents are compared to urban ones and (iii) main pharmaceuticals and other emerging compounds contents are compared in the two wastewaters. Finally, an overview of the removal capacity of the different treatments is reported.
The intraparticle diffusion model (IPD) proposed by Weber and Morris has been widely applied for the analysis of adsorption kinetics. In this work, the characteristic curves based on this model were plotted with various initial adsorption factors (Ri). Four zones of the initial adsorption according to Ri value from 0 to 1 were classified; that is, approaching completely initial adsorption (zone 4), strongly initial adsorption (zone 3), intermediately initial adsorption (zone 2), and weakly initial adsorption (zone 1). Activated carbons with micropore volume fraction of 0.537 and 0.686 were prepared from oil-palm shells by steam activation. Based on the standard deviations, the kinetics of the adsorption of tannic acid (TA), methylene blue (MB), phenol, and 4-chlorophenol (4-CP) on activated carbons could be best described by intraparticle diffusion model. The initial adsorption of TA and MB belonged to zone 2, and that of phenol and 4-CP mostly belonged to zone 3. Nearly 80% of the 86 adsorption systems surveyed belonged to zones 2 and 3, indicating that the Ri value was smaller when the carbon with smaller particle and steam-activated carbon was used.
In this research, the natural bentonite clay collected from Ashapura Clay Mines, Gujarat State, India, was utilized as a precursor to produce aluminium-pillared bentonite clay (Al-PILC) for the removal of cobalt(II) [Co(II)] ions from aqueous solutions. The original bentonite clay and Al-PILC were characterized with the help of chemical analyses, methylene blue (MB) adsorption isotherm, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR), while the thermal stability of the samples were studied using thermogravimetry (TG). Surface charge density of the samples as a function of pH was investigated using potentiometric titrations. Adsorption experiments were conducted under various conditions, i.e., pH, contact time, initial concentration, ionic strength, adsorbent dose and temperature. The most effective pH range for the removal of Co(II) ions was found to be 6.0–8.0. The maximum adsorption of 99.8% and 87.0% took place at pH 6.0 from an initial concentration of 10.0 and 25.0 mg l−1, respectively. Kinetic studies showed that an equilibrium time of 24 h was needed for the adsorption of Co(II) ions on Al-PILC and the experimental data were correlated by either the external mass transfer diffusion model for the first stage of adsorption and the intraparticle mass transfer diffusion model for the second stage of adsorption. The intraparticle mass transfer diffusion model gave a better fit to the experimental data. The Arrhenius and Eyring equations were applied to the data to determine the kinetic and thermodynamic parameters for explaining the theoretical behaviour of the adsorption process. The equilibrium isotherm data were analyzed using the Langmuir, Freundlich and Scatchard isotherm equations and the adsorption process was reflected by Freundlich isotherm. The efficiency of the Al-PILC was assessed by comparing the results with those on a commercial ion exchanger, Ceralite IRC-50. The suitability of the Al-PILC for treating Co(II) solutions was tested using simulated nuclear power plant coolant samples. Acid regeneration was tried for several cycles with a view to recover the adsorbed Co(II) and also to restore the adsorbent to its original state.
The methods for the determination of various types of oxygen surface functions on carbon materials are briefly described, and their relative advantages and problems that may arise are discussed. Acidimetric titration techniques, IR spectroscopy, XPS, thermal desorption spectroscopy, and electrokinetic measurements are described.
A literature review of the use of sorbents and biosorbents to treat polluted aqueous effluents containing dyes/organics or metal ions has been conducted. Over 70 systems have been reported since 1984 and over 43 of these reported the mechanism as being a pseudo-first order kinetic mechanism. Three sorption kinetic models are presented in this paper and have been used to test 11 of the literature systems previously reported as first order kinetics and one system previously reported as a second order process. In all 12 systems, the highest correlation coefficients were obtained for the pseudo-second order kinetic model.
The removal of an analgesic drug (acetaminophen) from water was investigated using activated carbons prepared from different residues, namely urban wastes (post-consumer plastics), and agro-industrial residues (cork powder and peach stones), comparing their adsorption capacity with that of commercially available carbonaceous adsorbents. The prepared carbon samples were evaluated on the basis of their adsorption capacities and kinetic performances, which were linked with their different properties. The samples prepared from chemical activation of the biomass residues show reasonably high removal efficiencies along with fast rate of adsorption, which are in fact comparable to commercial carbons. The analysis of the carbon samples after adsorbing the analgesic showed that adsorbent–adsorbate affinity is stronger in hydrophobic carbons of basic character that contain a well-developed microporosity. These characteristics are however not sufficient for an overall performance of a carbon in acetaminophen removal. The carbon must also have a well interconnected pore network (to facilitate the accessibility of acetaminophen molecules, thus speeding up adsorption kinetics) and an adequate chemical composition, which ultimately leads to a high adsorption capacity.
Adsorption of organic molecules from dilute aqueous solutions on carbon materials is a complex interplay between non-electrostatic and electrostatic interactions. Non-electrostatic interactions are essentially due to dispersion and hydrophobic interactions, whereas the electrostatic or coulombic interactions appear with electrolytes when they are ionized at the experimental conditions used. Both interactions depend on the characteristics of the adsorbent and the adsorptive and the solution chemistry. Among them the carbon surface chemistry has a great influence on both electrostatic and non-electrostatic interactions, and can be considered one of the main factors in the adsorption mechanism from dilute aqueous solutions. In this paper the current knowledge about the fundamental factors that control the adsorption process from aqueous phase will be presented.
Emerging organic contaminants (EOCs) detected in groundwater may have adverse effects on human health and aquatic ecosystems. This paper reviews the existing occurrence data in groundwater for a range of EOCs including pharmaceutical, personal care, 'life-style' and selected industrial compounds. The main sources and pathways for organic EOCs in groundwater are reviewed, with occurrence data for EOCs in groundwater included from both targeted studies and broad reconnaissance surveys. Nanogram-microgram per litre concentrations are present in groundwater for a large range of EOCs as well as metabolites and transformation products and under certain conditions may pose a threat to freshwater bodies for decades due to relatively long groundwater residence times. In the coming decades, more of these EOCs are likely to have drinking water standards, environmental quality standards and/or groundwater threshold values defined, and therefore a better understanding of the spatial and temporal variation remains a priority.
Analgesics are among the most widely used drugs and there is wide intercountry variability in the rates of consumption of different analgesics. Our objective is to determine and compare patterns of analgesic consumption in the Slovak Republic and a number of other European countries.
We undertook a drug utilization study using WHO ATC/defined daily doses (DDD) methodology. Wholesale analgesic data collected by the Slovak State Institute for Drug Control were used. Utilization was calculated as DDD per 1000 inhabitants per day. Comparison with wholesale data from Czech Republic, Estonia, Finland, Norway and Denmark, published on the Internet, was made.
Paracetamol/acetaminophen consumption varied only a little in Slovak Republic and Czech Republic, whereas consumption in Nordic countries was significantly higher (P < 0.05) and in Estonia significantly lower. Ibuprofen consumption was significantly higher in Czech Republic and Finland. Significantly lower consumption was in Norway. The lowest consumption of ASA/aspirin was in Denmark and in Norway. The highest consumption was in Finland.
Effective therapy needs good prescribing and well-informed prescribers and patients. Our study highlights wide differences in analgesic consumption even among similar European countries. The basis of these differences and their potential clinical impact require further investigation.
The removal of a widespread used drug (i.e., ibuprofen) from water was investigated using high valuable carbon adsorbents obtained from chemical and physical activation of a bioresource (cork) and a municipal waste (plastic). The waste-derived carbons outperformed the adsorption capacity of commercial carbonaceous adsorbents due to their adequate features for the removal of the targeted compound. Regarding the adsorption mechanism, the results obtained point out that ibuprofen retention is favored in activated carbons with basic surface properties. On the other hand, the textural features also play an important role; the presence of a transport pores network (i.e., mesopores) is crucial to ensure the accessibility to the inner porosity, and the microporosity must be large enough to accommodate the ibuprofen molecule. Specifically, adsorbents with a large fraction of ultramicropores (pore widths <0.7 nm) are not adequate to effectively remove ibuprofen.
Three samples of activated carbon were used for this study: two of wood and one of coal origin. The samples were further oxidized to study the effect of oxidation on the surface chemistry. The surface chemistry was characterized by using Boehm and potentiometric titrations, temperature-programmed desorption (TPD), and DRFTS. The results showed that oxidation introduces a variety of functional groups to the surface, making it more heterogeneous. Titration methods provide comparable results, whereas TPD detects more oxygen-containing groups. Discrepancies in the obtained results are due to limitations of the titration methods where only acidic and basic sites of certain strength can be detected. On the other hand, TPD can assess all functional groups but with less quantitative information. Moreover, comparison of TPD and titration methods leads to the detection of functional groups containing atoms other than oxygen and carbon as, for instance nitro groups, introduced to the carbon matrix via the nitration mechanism during oxidation with HNO(3). Copyright 2001 Academic Press.
Bamboo, an abundant and inexpensive natural resource in Malaysia was used to prepare activated carbon by physiochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO(2)) as the activating agents at 850 degrees C for 2h. The adsorption equilibrium and kinetics of methylene blue dye on such carbon were then examined at 30 degrees C. Adsorption isotherm of the methylene blue (MB) on the activated carbon was determined and correlated with common isotherm equations. The equilibrium data for methylene blue adsorption well fitted to the Langmuir equation, with maximum monolayer adsorption capacity of 454.2mg/g. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The adsorption of methylene blue could be best described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed.
Zur Theorie der sogenannten adsorption gelöster Stoffe
- S Lagergreen
Lagergreen, S.: Zur Theorie der sogenannten adsorption gelöster
Stoffe. Zeitschr f Chem und Ind der Kolloide. 2, 15-15 (1907).
https://doi.org/10.1007/BF01501332