Juan A. ConesaUniversity of Alicante | UA · Departamento de Ingeniería Química
Juan A. Conesa
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About
215
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Introduction
Additional affiliations
July 1996 - February 1997
September 1992 - present
Education
September 1987 - June 1992
University of Alicante
Field of study
- Chemistry
Publications
Publications (215)
In this study, the impact of bioplastic design on anaerobic digestion for biogas production was investigated. This research aims to facilitate the integration of bioplastics into a circular economy, which is why our study proposes considering not only aspects related to their degradation in the formulation but also ensuring efficient behavior in an...
This research delves into a detailed exploration of the thermal decomposition behavior of bio-based polymers, specifically thermoplastic starch (TPS) and polylactic acid (PLA), under varying heating rates in a nitrogen atmosphere. This study employs thermogravimetry (TG) to investigate, providing comprehensive insights into the thermal stability of...
This study examines the presence of bisphenol A (BPA), S (BPS), F (BPF), and M (BPM) in various recycled plastics readily available on the market (LDPE, HDPE, PET, and PP), in light of European Food Safety Authority (EFSA) limits. Twenty samples of different origin are analyzed, cleaning treatments are applied, and the migration potential of these...
The search for cleaner and more sustainable energy sources is increasingly growing. Aligning this demand with another environmental problem, such as sewage treatment/disposal, is a strategic priority. In light of this, the aim of this study was to estimate the energy potential of sewage generated in the Brazilian state of São Paulo (SP) by using it...
The scarcity of natural resources makes it essential to develop products that meet environmental requirements. This is also true for the water and wastewater treatment business, where even consolidated processes, such as coagulation and flocculation, must be improved, opening opportunities for searching for alternative options to conventional proce...
This research delves into a detailed exploration of the thermal decomposition behavior of bio-based polymers, specifically Thermoplastic Starch (TPS) and Poly(lactic acid) (PLA). The study focuses on the impact of three different heating rates under a nitrogen atmosphere, providing comprehensive insights into the thermal stability of these eco-frie...
Traditional techniques for removing fluoride (F⁻) from water are costly and complex, whereas phytoremediation is a less expensive method that can be adopted as an ecotechnological tool to control not only fluorine, but also other pollutants in urban and agricultural watersheds. Phytoremediation as a strategy for defluoridation is little used and st...
The debromination of waste circuit boards (WCBs) used in computer motherboards and components has been studied with two different pieces of equipment. Firstly, the reaction of small particles (around one millimeter in diameter) and larger pieces obtained from WCBs was carried out with several solutions of K2CO3 in small non-stirred batch reactors a...
In this work, briquettes from mattress waste are manufactured and the acoustic properties of the materials produced are checked. Briquettes are made at temperatures between 170 and 185 °C using waste from viscoelastic memory foam (VMF) and applying pressures between 25 and 75 MPa. Later, the properties of the materials such as their bulk density, p...
An effective management of waste printed circuit board (WCB) recycling presents significant advantages of an economic, social, and environmental nature. This is particularly the case when a suitable valorisation is made of the non-metallic parts of the WCBs, well known for their “hidden” toxicological risks. Such benefits motivate research on techn...
The great economic, social, and environmental interest that favors an effective management of the recycling of waste printed circuit boards (WCBs) encourages research on the improvement of processes capable of mitigating their harmful effects. In this work, the debromination of large WCBs was first performed through a hydrothermal process employing...
The presence of microplastics (MPs) in the environment, and the effects that the ingestion of these materials can have on organisms, can be aggravated by the adsorption of harmful substances on the surface or inside the MPs. Of special relevance are the studies that have been carried out on the adsorption and transport of polycyclic aromatic hydroc...
Residual biomass gasification is a promising route for the production of H2-rich syngas. However, the simultaneous formation of pollutants such as light hydrocarbons (HCs), benzene, toluene and xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during gasification must be controlle...
In the present work, recycled polyethylene (LDPE) samples of agricultural, post-commercial, post-industrial and post-consumer origin were selected and analysed. The analysis comprised the determination of different contaminants such as metals, polycyclic aromatic hydrocarbons (PAHs), dioxin-like biphenyl polychlorides (PCBs), and polychlorinated-di...
Water treatment generally does not specifically address the removal of microplastics (MPs). Nevertheless, treatment plants process water effectively, and the number of synthetic microparticles in effluents is usually very low. Still, discharge volumes from water-treatment plants are often elevated (reaching around 108 L/day), leading to the daily d...
The present study aims to determine the presence of synthetic polymeric microparticles (MPs) in samples of canned tuna. An analysis procedure of these microparticles was developed and tested. Four brands of tuna marketed in Ecuador canned both in water and oil were analysed. A significant presence of MPs was found: 692 ± 120 MPs/100g of tuna in wat...
With the objective of suppressing dioxins and furans (PCDD/Fs) emission in municipal solid waste incineration plants (MSWI), different chemical inhibitors have been tested. Among these inhibitors, nitrogen and sulphur compounds can significantly suppress PCDD/Fs formation via de novo synthesis, which gives very interesting results with very little...
Waste printed circuit boards (WCBs) were debrominated under hydrothermal treatment, using potassium carbonate as an alkaline additive to improve debromination efficiency (DE). Two different high-pressure reactors were used: a 1-L stirred reactor, where the evolution of the DE was followed over time at a low CO3²⁻/Br⁻ ratio (1:25), and an elementary...
The presence of different pollutants in recycled plastics is reviewed in this article. The desirable circular economy of plastics should be linked to the availability of clean recycled plastics with a non-significant and small to nil amount of substances of concern. Different researchers found polycyclic aromatic hydrocarbons (PAHs) and Persistent...
Persistent organic pollutant inhibition in the combustion process of polyvinyl chloride (PVC) by prior addition of an inhibitor is currently being studied, reducing the emission of pollutants, and thus reducing the large amount of waste PVC destined for landfill. In this work, the use of sewage sludge (SS) as an alternative to chemical inhibitors t...
Research abounds in the literature on kinetic analyses using thermogravimetric (TG) runs. Many of these studies use approximations of integral or derivative forms of the kinetic law and all of them use programmed temperatures. In the present work, a numerical integration procedure was discussed and applied to different examples. We focused on mater...
Research abounds in the literature on kinetic analyses using thermogravimetric (TG) runs. Many of these studies use approximations of integral or derivative forms of the kinetic law and all of them use programmed temperature, not the actual temperature measured by thermocouples close to the sample. In addition, it is common to conduct a single run...
A kinetic model has been developed for the formation of selected congeners of PCDD/Fs during the thermal decomposition of different wastes in a horizontal reactor. Previously published data on the decomposition of wastes have been correlated using a kinetic model that only considers process parameters, such as the presence of different amounts of o...
According to the latest research, marine products have the greatest potential for microplastic (MPs) contamination. Therefore, their presence in terrestrial food has not managed to attract much attention—despite the fact that in the future they may represent a serious environmental risk. Research conducted in Europe and the US has indicated the pre...
This preprint is focused in the presence of plastics and microplastics in food. We will discuss how many we eat, and how they arrive to the food, and why. We will treat many other things, such as the waste treatment in Europe and in Spain, with updated data; how much plastic waste is generated; what are microplastics and how they are analyzed, I wi...
Thermochemical processes for biomass conversion are promising to produce renewable hydrogen-rich syngas. In the present study, model fitting methods were used to propose thermal degradation kinetics during catalytic and non-catalytic pyrolysis (in N2) and combustion (in synthetic air) of sugarcane residual biomass. Catalytic processes were performe...
In our lab, we have been studying the emissions of different pollutants during pyrolysis and combustion of wastes under different conditions for the last three decades. These studies have focused on the effect of temperature and presence of oxygen on the production of different pollutants. Waste decomposition has been studied in a horizontal labora...
Plastics and microplastics in our food: how, how many and why. Analysis of the situation of waste management, especially focused on plastics. Microplastic degradation, food content, analysis.
This study investigates the geometric and electronic properties of selected BFRs in their ground (S0) and first singlet excited (S1) states deploying methods of the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). We estimate the effect of the S0→ S1 transition on the elongations of the C-Br bond, identify t...
Once removed from the sea, some plastics cannot be recycled or reused. This debris has high calorific value which makes it suitable to use as fuel. For this reason, a mixture of plastic materials was subjected to hydrothermal carbonization using seawater as solvent. We could thus examine the characteristics of the final products obtained and test t...
In order to reduce the calculation effort during the simulation of the emission of polychlorinated dibenzo-p-dioxins and furans (PCDD/F) during municipal solid waste incineration, minimizing the number of simulated components is mandatory. For this purpose, two new multilinear regression models capable of determining the dioxins total amount and to...
Dioxins and furans (PCDD/Fs), formed in any combustion process where carbon, oxygen, and chlorine are present, are an important subject of research because of their carcinogenicity. The emission of PCDD/Fs from agricultural waste combustion has been the object of numerous studies in the past. The chlorine and metal content of materials to be burnt...
In this chapter, the authors discuss the behavior of ideal reactors during the start‐up and shutdown of the flow, i.e. the unsteady state behavior of such systems. They increase the complexity of the differential equations to be solved, and in this way they begin with a continuous stirred tank reactor (CSTR) working in a dynamic regime. The authors...
One way of approaching the study of nonideal reactors is to consider them, in a first approximation, as if the flow model were the one corresponding to a continuously stirred tank reactor (CSTR) or a plug flow reactor. However, in real reactors, the nonideal flow model implies a minor conversion, so a method that allows for this conversion loss to...
Both pulse and step tracer input can be used to characterize the residence time distribution (RTD) in chemical reactors. This chapter presents the evolution of the output signal in a reactor for an arbitrary input of tracer. Also important are the systems where more than one reactor is combined in series. In this case, the signal entering the first...
Bioreactors or fermenters are classified according to the terminology used in the design of chemical reactors in stirred tank and tubular bioreactor. The biological reactions, under the point of view of kinetics and thermodynamics, present a series of own characteristics that differentiate them substantially from other processes of chemical transfo...
This chapter discusses the study of the phenomena related to the heat transfer during the process of scaling a chemical reactor. Batch reactors are frequently used for production of specialty chemicals such as cosmetics, medicines, etc. The hardest problems occur when people are dealing with exothermic reactions. In general, the histories of temper...
The rate of a catalytic reaction can be modified by the presence of certain substances, which are usually neither initial reactants nor products. These substances are called catalysts, and they produce an increase in the reaction rate. To be able to carry out a design of reactors for this type of reactions, it will be necessary to study in detail t...
It is important for the chemical engineer who must design a catalytic reactor to know not only the design equations but also the chemical fundaments of the catalysts that will be used in the industry. This chapter discusses the chemical bases of catalysis, with special reference to the most important industrial catalytic processes. It details the s...
This chapter gives an overview of the operation of chemical reactors in an unsteady regime, which is usually known by its acronym: forced unsteady state operation. Operation in an unsteady regime has been studied for more than 70 years, and during this time numerous studies have been published. They deal with ways to get a periodic operation, descr...
The partial differential equations are used in the mathematical formulation of processes of physics and other sciences that are usually distributed in space and time. Typical problems are the propagation of sound or heat, electrostatics, electrodynamics, fluid dynamics, elasticity, quantum mechanics, and many others. In chemical reaction engineerin...
Transfer function is a very useful concept for studying nonideal chemical reactors. The transfer function is defined as the quotient between the Laplace transform of the output function and the Laplace transform of the input function, under the assumption that the initial conditions are zero (equal to zero). This is valid for a linear and time‐inva...
Polyvinyl chloride (PVC) electric wires were subjected to dechlorination in subcritical water at three different temperatures in a high-pressure reactor. About 2.09, 73.08, and 95.96 wt % of chlorine in PVC wires was removed during dechlorination at 200 °C, 250 °C, and 300 °C, respectively. The solid residues were analyzed and characterized by ther...
Polyvinyl chloride (PVC) electric wires were subjected to dechlorination in subcritical water at three different temperatures in a high-pressure reactor. About 2.09, 73.08 and 95.96 wt. % of chlorine in PVC wires was removed during dechlorination at 200, 250 and 300 °C, respectively. The solid residues were analyzed and characterized by thermogravi...
Plastics are the most abundant products in the world and therefore also represent the largest volume of materials found in the sea. Their resistance to degradation makes them dangerous for the marine environment. In this study, the degradation of the four main plastics (Nylon, Polyethylene (PE), Polypropylene (PP), Polyethylene terephthalate (PET))...
Thermal decomposition of different samples containing a mixture of plastics (polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and nylon) combined with NaCl and metal oxides (Fe2O3, CuO) was studied under an air atmosphere at 850 °C using a reactor, followed by analysis of the evolved products. Combustion runs were performed...
Challenges of coupling steam reforming of ethanol (SRE) and carbon monoxide (CO) removal to continuous fuel-cell grade hydrogen (H2) production were assessed. A SRE reactor, based on a previous optimized RhPt/CeO2[ߝ]SiO2 catalyst, was coupled to a CO removal reactor, based on AuCu/CeO2 catalysts with different Au:Cu weight ratios. Fuel-cell grade H...
The inhibitory effect of thiourea (TUA), ammonium thiosulfate (TSA) and amidosulfonic acid (ASA) on the reactivity of fly ash air was investigated using a thermobalance at different heating rates (5, 10 and 20 K min-1). A model fly ash (activated carbon + 50 wt% CuCl2·2H2O, pyrolyzed at 700 °C and washed) was used as carbonaceous material. Adding C...
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
Four different types of fuel blends containing demolition and construction wood and household waste were combusted in a small-scale experimental set-up to study the effect of fuel composition on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), chlorobenzenes (PCBzs), chlorophenols (PCPhs) and poly...
The aim of this study was to determine the effect of the temperature and reaction time variables on the solid yield and the increment of heating values and composition of torrefied Dichrostachys cinerea wood by using a factorial experiment design and thermogravimetric analysis. The significant factors were identified by means of a two-level factori...
Combustion and pyrolysis runs at 850 °C were carried out in a laboratory scale horizontal reactor with different materials combining biomass and waste electrical and electronic equipment (WEEE). Analyses are presented of the carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated...
Marine debris is widely recognized as a global environmental problem. One of its main components, microplastics, has been found in several sea salt samples from different countries, indicating that sea products are irremediably contaminated by microplastics. Previous studies show very confusing results, reporting amounts of microparticles (MPs) in...
Heavy metal-loaded almond shell was subjected to pyrolysis to understand the effect of the presence of different heavy metals on its thermal degradation. Pyrolysis behavior of native and metal-loaded samples was studied by thermogravimetric analysis. Similar shapes of thermogravimetric curves indicate that the presence of cadmium (Cd), chromium (Cr...
Metal recovering through decomposition in the presence of steam of different wastes has been demonstrated to be an effective method. In the present work, three different types of copper clad laminates (FR4, CEM3 and ROGERS) were subjected to high temperature decomposition, analyzing their performance. Firstly, the samples were analyzed by thermogra...
Degradation of brominated flame retardants present in printed circuit boards (PCBs) was tested using subcritical water in a high pressure reactor. Debromination experiments were carried out in a batch stirred reactor at three different temperatures (225 °C, 250 °C and 275 °C) keeping a solid to liquid (S/L) ratio of PCB:water = 1:5 during 180 min....
In this study, the physical properties of briquettes produced from two different biomass feedstocks (sawdust and date palm trunk) and different plastic wastes, without using any external binding agent, were investigated. The biomass feedstocks were blended with different ratios of two waste from electrical and electronic equipment (WEEE) plastics (...
In this study, the physical properties of briquettes produced from two different biomass feedstocks (sawdust and date palm trunk) and different plastic wastes were investigated, without using any external binding agent. The biomass feedstocks were blended with different ratios of two WEEE plastics (halogen-free wire and print circuit boards (PCB))...
The production of flexible polyurethane foam (FPUF) briquettes has been tested at four different temperatures (160, 170, 180 and 190 °C) and with four different compacting pressures (17, 24, 35 and 48 MPa), selecting 180 °C and 35 MPa as the best briquetting conditions. In addition, heterogeneous briquettes have been moulded employing 10, 18 and 25...
This work is focused on the combustion processes of wood waste. Two kinds of waste have been studied: furniture wood waste (treated and used wood) and solid wood from factories (untreated wood). A kinetic study has been carried out for each material in air and an N2:O2 9:1 atmosphere with dynamic and dynamic + isothermal runs at different heating r...
Marine debris (MDs) produces a wide variety of negative environmental, economic, safety, health and cultural impacts. Most marine litter has a very low decomposition rate (plastics), leading to a gradual accumulation in the coastal and marine environment. Characterization of the MDs has been done in terms of their pollutant content: PAHs, ClBzs, Cl...
This study examined the emissions of powerful asthmatic agents called isocyanates from small-scale pyrolysis experiments of two common foams employed in mattress production such as flexible polyurethane foam (FPUF) and viscoelastic memory foam (VMF). A nitrogen atmosphere and five different temperatures, 300, 350, 400, 450 and 850 °C, were selected...
Gaseous emissions and ash obtained in the combustion of furniture waste have been studied, with particular emphasis on the emissions of hazardous pollutants, such as PCDD/Fs and dl-PCBS. Two different combustion procedures were carried out, one of them in a conventional residential stove (without an automatic control of combustion air and bad mixin...
Marine debris produces a wide variety of negative environmental, economic, safety, health and cultural impacts. Most marine litter has a very low decomposition rate (as plastics, which are the most abundant type of marine debris), leading to a gradual, but significant accumulation in the coastal and marine environment. Along that time, marine debri...
The disposal of waste from electrical and electronic equipment is an actual problem of industrialized countries. In the present work, thermal decomposition of different materials has been studied in a thermobalance at different heating rates. Kinetic models are proposed for the pyrolysis, gasification and combustion of crushed wood pellets (CWP), h...
Thermal degradation of viscoelastic memory foam (VMF) in a horizontal laboratory scale reactor has been studied. Pyrolysis and combustion experiments under sub-stoichiometric conditions were performed at four different temperatures (550 °C, 650 °C, 750 °C and 850 °C) for the determination of pollutants. Analyses of gas and semivolatile compounds, i...
The present work has been carried out to verify the feasibility of thermal valorization of an automobile shredder residue (ASR). With this aim, the thermal decomposition of this waste has been studied in a laboratory scale reactor, analyzing the pollutants emitted under different operating conditions. The emission factors of carbon oxides, light hy...
A systematic investigation of the thermal decomposition of viscoelastic memory foam (VMF) was performed using thermogravimetric analysis (TGA) to obtain the kinetic parameters, and thermogravimetric analysis coupled to Fourier Transformed Infrared Spectrometry (TGA-FTIR) and thermogravimetric analysis coupled to Mass Spectrometry (TGA-MS) to obtain...
The aim of the present work was to assess the emission of different persistent organic pollutants from a cement plant over a period of one year, under normal operational conditions. Thus, a long-term sampling device was installed in the clinker kiln stack of the cement plant. The factory uses petroleum coke as primary fuel, but also alternative fue...
Thermal characterization of coffee husk (Coffea arabica) from Colombian coffee has been studied. Different products, mostly volatile and semivolatile compounds, were analyzed, paying special attention to 16 polycyclic aromatic hydrocarbons (PAHs) classified by the United States Environmental Protection Agency (U.S. EPA) as priority pollutants, freq...
Thermal decomposition of flexible polyurethane foam (FPUF) was studied under nitrogen and air atmospheres at 550°C and 850°C using a laboratory scale reactor to analyse the evolved products. Ammonia, hydrogen cyanide and nitrile compounds were obtained in high yields in pyrolysis at the lower temperature, whereas at 850°C polycyclic aromatic hydroc...
Furniture waste is mainly composed of wood and upholstery foam (mostly polyurethane foam). Both of these have a high calorific value, therefore, energy recovery would be an appropriate process to manage these wastes. Nevertheless, the drawback is that the energy content of these wastes is limited due to their low density mainly that of upholstery f...
This work assessed the energy potential and alternative usages of biogas and sludge generated in upflow anaerobic sludge blanket reactors at the Laboreaux sewage treatment plant (STP), Brazil. Two scenarios were considered: (i) priority use of biogas for the thermal drying of dehydrated sludge and the use of the excess biogas for electricity genera...
Different types of crystalline carbon nanomaterials were used to reinforce polyaniline for use in electromechanical bilayer bending actuators. The objective is to analyze how the different graphitic structures of the nanocarbons affect and improve the in situ polymerized polyaniline composites and their subsequent actuator behavior. The nanocarbons...
The pyrolysis and combustion of automotive shredder residue (ASR) were studied by dynamic thermogravimetry and derivative thermogravimetry at heating rates of 5, 15 and 30 K min−1 at atmospheric pressure. For the simulation of pyrolysis and combustion processes, two different kinetic models are proposed. One of them is based on the distribution of...
CeO2-, ZrO2-, and La2O3-supported Rh-Pt catalysts were tested to assess their ability to catalyze the steam reforming of ethanol (SRE) for H2 production. SRE activity tests were performed using EtOH:H2O:N2 (molar ratio 1:3:51) at a gaseous space velocity of 70,600 h−1 between 400 and 700 °C at atmospheric pressure. The SRE stability of the catalyst...
The thermal decomposition of a solid recovered fuel has been studied using thermogravimetry, in order to get information about the main steps in the decomposition of such material. The study comprises two different atmospheres: inert and oxidative. The kinetics of decomposition is determined at three different heating rates using the same kinetic c...
The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/3...
In the present work, a very detailed study of the reforming of syngas produced in the decomposition of Posidonia oceanica is done. The effect of the presence of different amounts of dolomite is analysed. Also pyrolysis is studied, in nitrogen atmosphere, and gasification in the presence of air, oxygen and different amounts of steam. A detailed disc...
The present work aims to characterize the emissions from pyrolysis and combustion of waste PCB from mobile phones, before and after the removal of the metallic fraction, and at two different temperatures. The study comprises the analysis of gases, halogens and hydrogen halides, carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PA...
In the present work, a review of the data in literature concerning brominated dioxins and furans emissions has been done. Data has been found for different sources, including incineration units, vehicle exhaust, clinker furnaces, air sampling and metal treatment plants among other.