Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used a... more Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used as adsorbents in the recovery of Pb(II) ion and (W(VI)) oxyanion from synthetic solutions. The developed chars (both raw and activated) were thoroughly characterized to have insight about their textural and surface chemistry properties. H3PO4-activated chars presented lower surface areas than the raw chars and an acidic surface chemistry which affected the performance of these samples as they showed the lowest removals of the metallic ions. On the other hand, CO2-activated chars presented increased surface areas and increased mineral content compared to the raw chars, having presented higher uptake capacities for both Pb(II) (103–116 mg/g) and W(VI) (27–31 mg/g) ions. Cation exchange with Ca, Mg and Zn ions was appointed as a mechanism for Pb removal, as well as surface precipitation in the form of hydrocerussite (Pb3(CO3)2(OH)2). W(VI) adsorption might have been ruled by strong electrost...
The first step of this study comprised the characterization of six samples of raw bottom ash for ... more The first step of this study comprised the characterization of six samples of raw bottom ash for which the samples were collected in six different incineration plants located in four European countries, The collected bottom ash were submitted to a leaching assay performed in one batch extraction stage of 24 h, with a liquid/solid ration of 10. The leachites were characterized for 21 inorganic parameters and four biological indicators. The study's second step comprised the characterization of three new concrete formulations and a reference material. They were submitted to two different leaching tests: the European prestandard prEN 12457-2 and the French standard NF X 31-211. All leachites were characterized for the same chemical and biological parameters referred to above. The results demonstrated that the three new materials presented similar environmental risks and the ecotoxic levels similar to the reference material. The methodology proved to be an important tool for the envi...
Pyrolysis studies are being carried out with several waste materials with the goal of producing l... more Pyrolysis studies are being carried out with several waste materials with the goal of producing liquids that could be re-utilised in different end-use applications. The main aim of this work is to increase liquid yields produced by pyrolysis of various blends of plastics and biomass wastes. Polyethylene (PE), polypropylene (PP) and polystyrene (PS) were used as the plastic wastes component. Forestry residue pine was used as the biomass component. The presence of biomass waste decreased the liquid fraction but increased the gas fraction of the products, due to the high percentage of volatiles of the pine.
International Journal of Environmental Science and Technology, 2016
In the present study, a novel porous carbon obtained by K 2 CO 3 activation of potato peel waste ... more In the present study, a novel porous carbon obtained by K 2 CO 3 activation of potato peel waste under optimized conditions was applied for the first time as liquid-phase adsorbent of sodium diclofenac in parallel with a commercial activated carbon. The biomass-activated carbon presented an apparent surface area of 866 m 2 g-1 and well-developed microporous structure with a large amount of ultramicropores. The obtained carbon presented leaching and ecotoxicological properties compatible with its safe application to aqueous medium. Kinetic data of laboratorymade and commercial sample were best fitted by the pseudo-second-order model. The commercial carbon presented higher uptake of diclofenac, but the biomass carbon presented the higher adsorption rate which was associated with its higher hydrophilic nature which favoured external mass transfer. Both adsorbents presented adsorption isotherms that were best fitted by Langmuir model. The biomass carbon and the commercial carbon presented adsorption monolayer capacities of 69 and 146 mg g-1 , and Langmuir constants of 0.38 and 1.02 L mg-1 , respectively. The better performance of the commercial sample was related to its slightly higher micropore volume, but the most remarkable effect was the competition of water molecules in the biomass carbon.
In this paper, chemical and ecotoxicological data of leachates from bottom ashes collected in dif... more In this paper, chemical and ecotoxicological data of leachates from bottom ashes collected in different Municipal Solid Waste Incinerators (MSWI) are shown. The bottom ashes were collected in Belgium (three incinerators--samples B1 to B3), France, Germany, Italy and United Kingdom (one incinerator in each country--samples F1, D1, I1 and UK1, respectively). Both chemical and ecotoxicological characterizations of leachates were done on the framework of the European Directive 91/689/EEC and the European Council Decision 94/904/EC. This work was carried out under the European project called Valomat, which was supported by the European Commission through Brite-Euram III program. Twenty-one inorganic parameters were analyzed. The ecotoxicological assays were done under standard laboratory conditions, using the bacterium Photobacterium phosphoreum, the freshwater alga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the vegetable Lactuca sativa. Chemical data varied from sample to sample. Similar results were obtained in biological assays. The samples can be classified as ecotoxic/hazardous according to the French proposal for a Criterion and Evaluation Methods of Waste Ecotoxicity (CEMWE) and the German regulation on Hazardous Waste Classification (HWC). However, samples B1, B2, B3 and D1 comply the maximum limits for direct valorization category defined in the French Classification of Bottom Ashes based on their Polluting Potential (CBAPP). Sample B1 presented the lowest level of ecotoxicity, being considered as the most interesting to be used in the development of new materials for civil engineering works.
Char residues produced in co-pyrolysis of different wastes were characterized through chemical an... more Char residues produced in co-pyrolysis of different wastes were characterized through chemical and toxicity tests. A fraction of the solid chars was treated by extraction with dichloromethane. Different volatilit fractions present in the extracted and non extrated char ...
The effectiveness of chars from the co-pyrolysis of pine, used tires and plastic wastes for the r... more The effectiveness of chars from the co-pyrolysis of pine, used tires and plastic wastes for the removal of lead (Pb(2+)) from aqueous medium, was investigated. The chars were predominantly of macroporous nature, but the introduction of tires in the pyrolysis feedstock enhanced their mesoporous content as well as surface area. Pb(2+) sorption with the chars was a slow and unstable process in which sorption-desorption seems to be competing. The highest Pb(2+) removal (88%) was attained by the char resulting from the pyrolysis of a mixture composed by equal mass ratios of used tires and plastics, at 48 h of contact time. This char was also the one with the overall better performance for Pb(2+) sorption, achieving almost 100% of Pb(2+) removal on the study of the effect of adsorbent dose. Mixing the three raw materials for pyrolysis had no advantage for the resulting char concerning the removal efficiency of Pb(2+). The sorption mechanisms varied according to the pyrolysis feedstock: in chars from feedstock with pine, chemisorption involving complexation with oxygenated surface functional groups followed by cation exchange was the presumable mechanism. In tire rubber derived chars, cation exchange with Ca(2+), K(+), and Zn(2+) played the major role on Pb(2+) sorption.
A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produce... more A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produced during the co-pyrolysis of plastics and pine biomass was developed. In a first step, several sampling techniques (headspace solid phase microextraction (HS-SPME), static headspace sampling (HS), and dispersive liquid-liquid microextraction (DLLME) were compared in order to evaluate their sensitivity towards these analytes. HS-SPME and HS sampling had the better performance, but DLLME was itself as a technique able to extract volatiles with a significant enrichment factor. HS sampling coupled with GC-MS was chosen for method validation for the analytes tested. Calibration curves were constructed for each analyte with correlation coefficients higher than 0.999. The limits of detection were in the range of 0.66-37.85 ng/L. The precision of the HS method was evaluated and good repeatability was achieved with relative standard deviations of 4.8-13.2%. The recoveries of the analytes were evaluated by analysing fortified real eluate samples and were in the range of 60.6-113.9%. The validated method was applied in real eluate samples. Benzene, toluene, ethylbenzene and xylenes (BTEX) were the compounds in higher concentrations. The DLLME technique coupled with GC-MS was used to investigate the presence of less volatile contaminants in eluate samples. This analysis revealed the presence of significant amounts of alkyl phenols and other aromatic compounds with appreciable water solubility.
Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experi... more Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experience has amply demonstrated that solids exposed to the oxygen-deficient plasma flame are converted to liquid, and liquid exposed to the same flame is converted to gas. A low amount of vitrified solid residue material usually remains at the end of this process. Plasma
The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal val... more The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal treatment have not been fully studied. Two combustion tests were performed in a fluidized bed combustor. Colombian coal was used as fuel in test A. A blend (1+1) of this coal and a stabilized SS (Biogran) was used in a second test B. Samples of the bottom and fly ashes trapped in two sequential cyclones were collected. The characterization of the ashes was focused on two main aspects: (1) the bulk content of a set of metals and (2) the characterization of eluates produced according to the European Standard leaching test EN 12457-2. The eluates were submitted to an ecotoxicological characterization for two bio-indicators. In what concerns the bulk content of ashes, both combustion tests have produced ashes with different compositions. The ashes formed during the co-combustion test have shown higher concentrations of metals, namely Cr, Cu, Ni, Pb, Zn and Fe for all ashes. The leaching test has shown low mobility of these elements from the by-products produced during the combustion and co-combustion tests. Cr and Cr(VI) were mainly detected in the eluates of the 1st cyclone ashes produced in both combustion tests and in the 2nd cyclone ashes produced in the co-combustion test. Considering the ecotoxicity assays, the eluates of bottom and fly ashes for both combustion and co-combustion tests have shown low ecotoxic levels. The micro-crustacean Daphnia magna was generally more sensitive than the bacterium Vibrio fischeri. CEMWE criterion has allowed to classify the bottom ashes for both combustion and co-combustion tests as non-toxic residues and the fly ashes collected in both cyclones as toxic.
The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of P... more The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of PE, PP and PS plastic wastes, pine biomass and used tires. The quality of the upgraded chars was evaluated by measuring some of their physico-chemical properties in order to assess their valorisation as adsorbents' precursors. The crude chars were submitted to a sequential solvent extraction with organic solvents of increasing polarity (hexane, mixture 1:1 v/v hexane:acetone and acetone) followed by an acidic demineralization procedure with 1M HCl solution. The results obtained showed that the upgrading treatment allow the recovery of 63-81% of the pyrolysis oils trapped in the crude chars and a reduction in the char's ash content in the range of 64-86%. The textural and adsorption properties of the upgraded chars were evaluated and the results indicate that the chars are mainly mesoporous and macroporous materials, with adsorption capacities in the range of 3.59-22.2 mg/g for the methylene blue dye. The upgrading treatment allowed to obtain carbonaceous materials with quality to be reused as adsorbents or as precursors for activated carbon.
The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route... more The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route for this residue. Nevertheless, the properties of ashes produced need to be studied. To evaluate these properties, three combustion tests were performed in a ...
A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produce... more A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produced during the co-pyrolysis of plastics and pine biomass was developed. In a first step, several sampling techniques (headspace solid phase microextraction (HS-SPME), static headspace sampling (HS), and dispersive liquid-liquid microextraction (DLLME) were compared in order to evaluate their sensitivity towards these analytes. HS-SPME and HS sampling had the better performance, but DLLME was itself as a technique able to extract volatiles with a significant enrichment factor. HS sampling coupled with GC-MS was chosen for method validation for the analytes tested. Calibration curves were constructed for each analyte with correlation coefficients higher than 0.999. The limits of detection were in the range of 0.66-37.85 ng/L. The precision of the HS method was evaluated and good repeatability was achieved with relative standard deviations of 4.8-13.2%. The recoveries of the analytes were evaluated by analysing fortified real eluate samples and were in the range of 60.6-113.9%. The validated method was applied in real eluate samples. Benzene, toluene, ethylbenzene and xylenes (BTEX) were the compounds in higher concentrations. The DLLME technique coupled with GC-MS was used to investigate the presence of less volatile contaminants in eluate samples. This analysis revealed the presence of significant amounts of alkyl phenols and other aromatic compounds with appreciable water solubility.
The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of P... more The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of PE, PP and PS plastic wastes, pine biomass and used tires. The quality of the upgraded chars was evaluated by measuring some of their physico-chemical properties in order to assess their valorisation as adsorbents' precursors. The crude chars were submitted to a sequential solvent extraction with organic solvents of increasing polarity (hexane, mixture 1:1 v/v hexane:acetone and acetone) followed by an acidic demineralization procedure with 1M HCl solution. The results obtained showed that the upgrading treatment allow the recovery of 63-81% of the pyrolysis oils trapped in the crude chars and a reduction in the char's ash content in the range of 64-86%. The textural and adsorption properties of the upgraded chars were evaluated and the results indicate that the chars are mainly mesoporous and macroporous materials, with adsorption capacities in the range of 3.59-22.2 mg/g for the methylene blue dye. The upgrading treatment allowed to obtain carbonaceous materials with quality to be reused as adsorbents or as precursors for activated carbon.
Résumé/Abstract Two combustion tests were performed in a fluidized bed combustor of a thermo-elec... more Résumé/Abstract Two combustion tests were performed in a fluidized bed combustor of a thermo-electric power plant:(1) combustion of coal;(2) co-combustion of coal (68.7% w/w), sewage sludge (9.2% w/w) and meat and bone meal (MBM)(22.1% w/w). Three samples ...
ABSTRACT The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorizat... more ABSTRACT The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route for this residue. Nevertheless, the properties of ashes produced need to be studied. To evaluate these properties, three combustion tests were performed in a fluidized bed reactor: 1) coal combustion; 2) coal + MBM (85% + 15%) co-combustion; 3) MBM combustion. The characterization of ashes was focused on the following aspects: (1) Determination of bulk content of Cr, Zn, Ni, Cu, Pb, Cd, Hg, As, Ba, Mo, Sb, Se, Ca, Na, Mg, Fe, Al and K; (2) Leaching properties of ashes based on the European Standard EN12457-2. The eluates were characterized for some of the metals referred above and for Cr VI, CN−, pH, Cl−, F−, SO42−, dissolved organic carbon and total dissolved solids. The eluates were also characterized for ecotoxicological levels by using the following bio-indicators: bacterium V. fischeri, microalgae S. capricornutum and microcrustacean D. magna. The ashes produced in the combustion of coal and co-combustion of coal + MBM have not shown evidences of ecotoxicity, while the ashes produced in the combustion of MBM were classified as ecotoxic. An assessment of the relationship between the chemical and the ecotoxicological properties of the ashes was performed. pH seemed to be the chemical parameter that most influences the ecotoxicological level of ashes.
The present work is devoted to the study chars obtained in the co-pyrolisis of plastics, biomass ... more The present work is devoted to the study chars obtained in the co-pyrolisis of plastics, biomass and tyres wastes. The composition of these chars is not yet well studied and only recent an attempt was made by the aithors to provide some information about the ...
Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used a... more Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used as adsorbents in the recovery of Pb(II) ion and (W(VI)) oxyanion from synthetic solutions. The developed chars (both raw and activated) were thoroughly characterized to have insight about their textural and surface chemistry properties. H3PO4-activated chars presented lower surface areas than the raw chars and an acidic surface chemistry which affected the performance of these samples as they showed the lowest removals of the metallic ions. On the other hand, CO2-activated chars presented increased surface areas and increased mineral content compared to the raw chars, having presented higher uptake capacities for both Pb(II) (103–116 mg/g) and W(VI) (27–31 mg/g) ions. Cation exchange with Ca, Mg and Zn ions was appointed as a mechanism for Pb removal, as well as surface precipitation in the form of hydrocerussite (Pb3(CO3)2(OH)2). W(VI) adsorption might have been ruled by strong electrost...
The first step of this study comprised the characterization of six samples of raw bottom ash for ... more The first step of this study comprised the characterization of six samples of raw bottom ash for which the samples were collected in six different incineration plants located in four European countries, The collected bottom ash were submitted to a leaching assay performed in one batch extraction stage of 24 h, with a liquid/solid ration of 10. The leachites were characterized for 21 inorganic parameters and four biological indicators. The study's second step comprised the characterization of three new concrete formulations and a reference material. They were submitted to two different leaching tests: the European prestandard prEN 12457-2 and the French standard NF X 31-211. All leachites were characterized for the same chemical and biological parameters referred to above. The results demonstrated that the three new materials presented similar environmental risks and the ecotoxic levels similar to the reference material. The methodology proved to be an important tool for the envi...
Pyrolysis studies are being carried out with several waste materials with the goal of producing l... more Pyrolysis studies are being carried out with several waste materials with the goal of producing liquids that could be re-utilised in different end-use applications. The main aim of this work is to increase liquid yields produced by pyrolysis of various blends of plastics and biomass wastes. Polyethylene (PE), polypropylene (PP) and polystyrene (PS) were used as the plastic wastes component. Forestry residue pine was used as the biomass component. The presence of biomass waste decreased the liquid fraction but increased the gas fraction of the products, due to the high percentage of volatiles of the pine.
International Journal of Environmental Science and Technology, 2016
In the present study, a novel porous carbon obtained by K 2 CO 3 activation of potato peel waste ... more In the present study, a novel porous carbon obtained by K 2 CO 3 activation of potato peel waste under optimized conditions was applied for the first time as liquid-phase adsorbent of sodium diclofenac in parallel with a commercial activated carbon. The biomass-activated carbon presented an apparent surface area of 866 m 2 g-1 and well-developed microporous structure with a large amount of ultramicropores. The obtained carbon presented leaching and ecotoxicological properties compatible with its safe application to aqueous medium. Kinetic data of laboratorymade and commercial sample were best fitted by the pseudo-second-order model. The commercial carbon presented higher uptake of diclofenac, but the biomass carbon presented the higher adsorption rate which was associated with its higher hydrophilic nature which favoured external mass transfer. Both adsorbents presented adsorption isotherms that were best fitted by Langmuir model. The biomass carbon and the commercial carbon presented adsorption monolayer capacities of 69 and 146 mg g-1 , and Langmuir constants of 0.38 and 1.02 L mg-1 , respectively. The better performance of the commercial sample was related to its slightly higher micropore volume, but the most remarkable effect was the competition of water molecules in the biomass carbon.
In this paper, chemical and ecotoxicological data of leachates from bottom ashes collected in dif... more In this paper, chemical and ecotoxicological data of leachates from bottom ashes collected in different Municipal Solid Waste Incinerators (MSWI) are shown. The bottom ashes were collected in Belgium (three incinerators--samples B1 to B3), France, Germany, Italy and United Kingdom (one incinerator in each country--samples F1, D1, I1 and UK1, respectively). Both chemical and ecotoxicological characterizations of leachates were done on the framework of the European Directive 91/689/EEC and the European Council Decision 94/904/EC. This work was carried out under the European project called Valomat, which was supported by the European Commission through Brite-Euram III program. Twenty-one inorganic parameters were analyzed. The ecotoxicological assays were done under standard laboratory conditions, using the bacterium Photobacterium phosphoreum, the freshwater alga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the vegetable Lactuca sativa. Chemical data varied from sample to sample. Similar results were obtained in biological assays. The samples can be classified as ecotoxic/hazardous according to the French proposal for a Criterion and Evaluation Methods of Waste Ecotoxicity (CEMWE) and the German regulation on Hazardous Waste Classification (HWC). However, samples B1, B2, B3 and D1 comply the maximum limits for direct valorization category defined in the French Classification of Bottom Ashes based on their Polluting Potential (CBAPP). Sample B1 presented the lowest level of ecotoxicity, being considered as the most interesting to be used in the development of new materials for civil engineering works.
Char residues produced in co-pyrolysis of different wastes were characterized through chemical an... more Char residues produced in co-pyrolysis of different wastes were characterized through chemical and toxicity tests. A fraction of the solid chars was treated by extraction with dichloromethane. Different volatilit fractions present in the extracted and non extrated char ...
The effectiveness of chars from the co-pyrolysis of pine, used tires and plastic wastes for the r... more The effectiveness of chars from the co-pyrolysis of pine, used tires and plastic wastes for the removal of lead (Pb(2+)) from aqueous medium, was investigated. The chars were predominantly of macroporous nature, but the introduction of tires in the pyrolysis feedstock enhanced their mesoporous content as well as surface area. Pb(2+) sorption with the chars was a slow and unstable process in which sorption-desorption seems to be competing. The highest Pb(2+) removal (88%) was attained by the char resulting from the pyrolysis of a mixture composed by equal mass ratios of used tires and plastics, at 48 h of contact time. This char was also the one with the overall better performance for Pb(2+) sorption, achieving almost 100% of Pb(2+) removal on the study of the effect of adsorbent dose. Mixing the three raw materials for pyrolysis had no advantage for the resulting char concerning the removal efficiency of Pb(2+). The sorption mechanisms varied according to the pyrolysis feedstock: in chars from feedstock with pine, chemisorption involving complexation with oxygenated surface functional groups followed by cation exchange was the presumable mechanism. In tire rubber derived chars, cation exchange with Ca(2+), K(+), and Zn(2+) played the major role on Pb(2+) sorption.
A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produce... more A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produced during the co-pyrolysis of plastics and pine biomass was developed. In a first step, several sampling techniques (headspace solid phase microextraction (HS-SPME), static headspace sampling (HS), and dispersive liquid-liquid microextraction (DLLME) were compared in order to evaluate their sensitivity towards these analytes. HS-SPME and HS sampling had the better performance, but DLLME was itself as a technique able to extract volatiles with a significant enrichment factor. HS sampling coupled with GC-MS was chosen for method validation for the analytes tested. Calibration curves were constructed for each analyte with correlation coefficients higher than 0.999. The limits of detection were in the range of 0.66-37.85 ng/L. The precision of the HS method was evaluated and good repeatability was achieved with relative standard deviations of 4.8-13.2%. The recoveries of the analytes were evaluated by analysing fortified real eluate samples and were in the range of 60.6-113.9%. The validated method was applied in real eluate samples. Benzene, toluene, ethylbenzene and xylenes (BTEX) were the compounds in higher concentrations. The DLLME technique coupled with GC-MS was used to investigate the presence of less volatile contaminants in eluate samples. This analysis revealed the presence of significant amounts of alkyl phenols and other aromatic compounds with appreciable water solubility.
Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experi... more Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experience has amply demonstrated that solids exposed to the oxygen-deficient plasma flame are converted to liquid, and liquid exposed to the same flame is converted to gas. A low amount of vitrified solid residue material usually remains at the end of this process. Plasma
The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal val... more The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal treatment have not been fully studied. Two combustion tests were performed in a fluidized bed combustor. Colombian coal was used as fuel in test A. A blend (1+1) of this coal and a stabilized SS (Biogran) was used in a second test B. Samples of the bottom and fly ashes trapped in two sequential cyclones were collected. The characterization of the ashes was focused on two main aspects: (1) the bulk content of a set of metals and (2) the characterization of eluates produced according to the European Standard leaching test EN 12457-2. The eluates were submitted to an ecotoxicological characterization for two bio-indicators. In what concerns the bulk content of ashes, both combustion tests have produced ashes with different compositions. The ashes formed during the co-combustion test have shown higher concentrations of metals, namely Cr, Cu, Ni, Pb, Zn and Fe for all ashes. The leaching test has shown low mobility of these elements from the by-products produced during the combustion and co-combustion tests. Cr and Cr(VI) were mainly detected in the eluates of the 1st cyclone ashes produced in both combustion tests and in the 2nd cyclone ashes produced in the co-combustion test. Considering the ecotoxicity assays, the eluates of bottom and fly ashes for both combustion and co-combustion tests have shown low ecotoxic levels. The micro-crustacean Daphnia magna was generally more sensitive than the bacterium Vibrio fischeri. CEMWE criterion has allowed to classify the bottom ashes for both combustion and co-combustion tests as non-toxic residues and the fly ashes collected in both cyclones as toxic.
The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of P... more The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of PE, PP and PS plastic wastes, pine biomass and used tires. The quality of the upgraded chars was evaluated by measuring some of their physico-chemical properties in order to assess their valorisation as adsorbents' precursors. The crude chars were submitted to a sequential solvent extraction with organic solvents of increasing polarity (hexane, mixture 1:1 v/v hexane:acetone and acetone) followed by an acidic demineralization procedure with 1M HCl solution. The results obtained showed that the upgrading treatment allow the recovery of 63-81% of the pyrolysis oils trapped in the crude chars and a reduction in the char's ash content in the range of 64-86%. The textural and adsorption properties of the upgraded chars were evaluated and the results indicate that the chars are mainly mesoporous and macroporous materials, with adsorption capacities in the range of 3.59-22.2 mg/g for the methylene blue dye. The upgrading treatment allowed to obtain carbonaceous materials with quality to be reused as adsorbents or as precursors for activated carbon.
The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route... more The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route for this residue. Nevertheless, the properties of ashes produced need to be studied. To evaluate these properties, three combustion tests were performed in a ...
A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produce... more A method for the determination of 15 aromatic hydrocarbons in eluates from solid residues produced during the co-pyrolysis of plastics and pine biomass was developed. In a first step, several sampling techniques (headspace solid phase microextraction (HS-SPME), static headspace sampling (HS), and dispersive liquid-liquid microextraction (DLLME) were compared in order to evaluate their sensitivity towards these analytes. HS-SPME and HS sampling had the better performance, but DLLME was itself as a technique able to extract volatiles with a significant enrichment factor. HS sampling coupled with GC-MS was chosen for method validation for the analytes tested. Calibration curves were constructed for each analyte with correlation coefficients higher than 0.999. The limits of detection were in the range of 0.66-37.85 ng/L. The precision of the HS method was evaluated and good repeatability was achieved with relative standard deviations of 4.8-13.2%. The recoveries of the analytes were evaluated by analysing fortified real eluate samples and were in the range of 60.6-113.9%. The validated method was applied in real eluate samples. Benzene, toluene, ethylbenzene and xylenes (BTEX) were the compounds in higher concentrations. The DLLME technique coupled with GC-MS was used to investigate the presence of less volatile contaminants in eluate samples. This analysis revealed the presence of significant amounts of alkyl phenols and other aromatic compounds with appreciable water solubility.
The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of P... more The present work aims to perform a multistep upgrading of chars obtained in the co-pyrolysis of PE, PP and PS plastic wastes, pine biomass and used tires. The quality of the upgraded chars was evaluated by measuring some of their physico-chemical properties in order to assess their valorisation as adsorbents' precursors. The crude chars were submitted to a sequential solvent extraction with organic solvents of increasing polarity (hexane, mixture 1:1 v/v hexane:acetone and acetone) followed by an acidic demineralization procedure with 1M HCl solution. The results obtained showed that the upgrading treatment allow the recovery of 63-81% of the pyrolysis oils trapped in the crude chars and a reduction in the char's ash content in the range of 64-86%. The textural and adsorption properties of the upgraded chars were evaluated and the results indicate that the chars are mainly mesoporous and macroporous materials, with adsorption capacities in the range of 3.59-22.2 mg/g for the methylene blue dye. The upgrading treatment allowed to obtain carbonaceous materials with quality to be reused as adsorbents or as precursors for activated carbon.
Résumé/Abstract Two combustion tests were performed in a fluidized bed combustor of a thermo-elec... more Résumé/Abstract Two combustion tests were performed in a fluidized bed combustor of a thermo-electric power plant:(1) combustion of coal;(2) co-combustion of coal (68.7% w/w), sewage sludge (9.2% w/w) and meat and bone meal (MBM)(22.1% w/w). Three samples ...
ABSTRACT The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorizat... more ABSTRACT The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route for this residue. Nevertheless, the properties of ashes produced need to be studied. To evaluate these properties, three combustion tests were performed in a fluidized bed reactor: 1) coal combustion; 2) coal + MBM (85% + 15%) co-combustion; 3) MBM combustion. The characterization of ashes was focused on the following aspects: (1) Determination of bulk content of Cr, Zn, Ni, Cu, Pb, Cd, Hg, As, Ba, Mo, Sb, Se, Ca, Na, Mg, Fe, Al and K; (2) Leaching properties of ashes based on the European Standard EN12457-2. The eluates were characterized for some of the metals referred above and for Cr VI, CN−, pH, Cl−, F−, SO42−, dissolved organic carbon and total dissolved solids. The eluates were also characterized for ecotoxicological levels by using the following bio-indicators: bacterium V. fischeri, microalgae S. capricornutum and microcrustacean D. magna. The ashes produced in the combustion of coal and co-combustion of coal + MBM have not shown evidences of ecotoxicity, while the ashes produced in the combustion of MBM were classified as ecotoxic. An assessment of the relationship between the chemical and the ecotoxicological properties of the ashes was performed. pH seemed to be the chemical parameter that most influences the ecotoxicological level of ashes.
The present work is devoted to the study chars obtained in the co-pyrolisis of plastics, biomass ... more The present work is devoted to the study chars obtained in the co-pyrolisis of plastics, biomass and tyres wastes. The composition of these chars is not yet well studied and only recent an attempt was made by the aithors to provide some information about the ...
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