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Rob N.j. Comans - One of the best experts on this subject based on the ideXlab platform.
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contribution of natural organic matter to copper leaching from municipal solid Waste Incinerator bottom ash
Environmental Science & Technology, 2004Co-Authors: And Andre Van Zomere, Rob N.j. ComansAbstract:The leaching of heavy metals, such as copper, from municipal solid Waste Incinerator (MSWI) bottom ash is a concern in many countries and may inhibit the beneficial reuse of this secondary material. The enhanced leaching of copper from three MSWI bottom ash samples by dissolved organic carbon (DOC) was investigated with specific attention for the nature of the organic ligands. A competitive ligand exchange-solvent extraction (CLE-SE) method was used to measure Cu binding to DOC. Two types of binding sites for Cu were identified and geochemical modeling showed that the organically bound fraction varied from 82% to 100% between pH 6.6 and 10.6. Model calculations showed that complexation by previously identified aliphatic and aromatic acids was unable to explain the enhanced Cu leaching from the MSWI residues. High-performance size-exclusion chromatography (HPSEC) and the standard extraction procedure to isolate and purify natural organic matter revealed that about 0.5% of DOC consists of humic acids and 14.3-25.6% consists of fulvic acids. Calculated Cu binding isotherms based on these natural organic compounds, and the nonideal competitive adsorption-Donnan (NICA-Donnan) model, provide an adequate description of the organic Cu complexation in the bottom ash leachates. The results show that fulvic acid-type components exist in MSWI bottom ash leachates and are likely responsible for the generally observed enhanced Cu leaching from these residues. These findings enable the use of geochemical speciation programs, which include models and intrinsic parameters for metal binding to natural organic matter, to predict Cu leaching from this widely produced Waste material under variable environmental conditions (e.g., pH, ionic strength, and concentrations of competing metals). The identified role of fulvic acids in the leaching of Cu and possibly other heavy metals can also be used in the development of techniques to improve the environmental quality of MSWI bottom ash
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contribution of natural organic matter to copper leaching from municipal solid Waste Incinerator bottom ash
Environmental Science & Technology, 2004Co-Authors: A Van Zomeren, Rob N.j. ComansAbstract:The leaching of heavy metals, such as copper, from municipal solid Waste Incinerator (MSWI) bottom ash is a concern in many countries and may inhibit the beneficial reuse of this secondary material. The enhanced leaching of copper from three MSWI bottom ash samples by dissolved organic carbon (DOC) was investigated with specific attention for the nature of the organic ligands. A competitive ligand exchange-solvent extraction (CLE-SE) method was used to measure Cu binding to DOC. Two types of binding sites for Cu were identified and geochemical modeling showed that the organically bound fraction varied from 82% to 100% between pH 6.6 and 10.6. Model calculations showed that complexation by previously identified aliphatic and aromatic acids was unable to explain the enhanced Cu leaching from the MSWI residues. High-performance size-exclusion chromatography (HPSEC) and the standard extraction procedure to isolate and purify natural organic matter revealed that about 0.5% of DOC consists of humic acids and 14.3-25.6% consists of fulvic acids. Calculated Cu binding isotherms based on these natural organic compounds, and the nonideal competitive adsorption-Donnan (NICA-Donnan) model, provide an adequate description of the organic Cu complexation in the bottom ash leachates. The results show that fulvic acid-type components exist in MSWI bottom ash leachates and are likely responsible for the generally observed enhanced Cu leaching from these residues. These findings enable the use of geochemical speciation programs, which include models and intrinsic parameters for metal binding to natural organic matter, to predict Cu leaching from this widely produced Waste material under variable environmental conditions (e.g., pH, ionic strength, and concentrations of competing metals). The identified role of fulvic acids in the leaching of Cu and possibly other heavy metals can also be used in the development of techniques to improve the environmental quality of MSWI bottom ash
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carbonation processes in municipal solid Waste Incinerator bottom ash and their effect on the leaching of copper and molybdenum
Applied Geochemistry, 2002Co-Authors: Jeanne A Meima, Renata Dorothea Van Der Weijde, Taylo T Eighmy, Rob N.j. ComansAbstract:The interaction of CO2 with municipal solid Waste Incinerator (MSWI) bottom ash was studied in order to investigate the resulting changes in pH and bottom ash mineralogy and the impact that these changes have on the mobility of Cu and Mo. Carefully controlled carbonation experiments were performed on bottom ash suspensions and on filtered bottom ash leachates. Changes in leachate composition were interpreted with the geochemical model MINTEQA2, and neoformed minerals were investigated by means of chemical and spectroscopic analysis. The leaching of Cu and Mo during artificial carbonation is compared to the leachability of Cu and Mo from a sample of naturally carbonated bottom ash from the same Incinerator. During carbonation in the laboratory, a precipitate was formed that consisted mainly of Al-rich amorphous material, calcite, and possibly gibbsite. Carbonation to pH ≈8.3 resulted in a reduction of more than 50% in Cu leaching, and a reduction of less than 3% in Mo leaching. The reduction in Cu leaching is attributed to sorption to the neoformed amorphous Al-minerals. During natural weathering/carbonation of bottom ash, additional sorption sites are formed which further reduce the leaching of Cu and Mo on a time scale of months to years.
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complexation of cu with dissolved organic carbon in municipal solid Waste Incinerator bottom ash leachates
Environmental Science & Technology, 1999Co-Authors: Jeanne A Meima, And Andre Van Zomere, Rob N.j. ComansAbstract:The complexation of Cu with dissolved organic carbon (DOC) in leachates from fresh and 1.5-year old municipal solid Waste Incinerator (MSWI) bottom ash was studied using a competitive ligand-exchange solvent extraction procedure. At least two different ligands appear to be involved in the complexation of copper with DOC. The dissolved Cu appears to be 95−100% organically bound in leachates from both the fresh and the weathered bottom ash, and geochemical modeling indicates that the leaching of Cu from these ashes is primarily controlled by the availability of the organic ligands in the bottom ash. The mechanism that binds Cu to the solid phase is likely to be tenorite in the fresh bottom ash, and sorption to amorphous Fe/Al−(hydr)oxides in the weathered bottom ash.
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the leaching of trace elements from municipal solid Waste Incinerator bottom ash at different stages of weathering
Applied Geochemistry, 1999Co-Authors: Jeanne A Meima, Rob N.j. ComansAbstract:For a proper assessment of the environmental impact of the utilisation and disposal of Municipal Solid Waste Incinerator (MSWI) bottom ash it is necessary to understand weathering processes and their effects on (trace) element leaching. The authors have investigated the processes that control the leaching of Cd, Pb, Zn, Cu, and Mo from 3 categories of bottom ash: (A) unweathered bottom ash (grate siftings and unquenched samples), (B) quenched/non-carbonated bottom ash (freshly quenched and 6-week-old samples), and (C) weathered bottom ash (1.5- and 12-year-old samples). Leaching experiments were performed in a pH-stat at a large range of pH values. The speciation code MINTEQA2 was used for subsequent modelling of precipitation/dissolution processes. The speciation of trace elements in weathered bottom ash was also investigated by microanalytical techniques. In A- and B-type bottom ash the general controlling processes are thought to be precipitation/dissolution of relatively soluble minerals or, in the case of Cu in particular, extensive complexation with dissolved organic C. At the 'natural' pH of the samples, the leaching of Cd, Pb, Cu, Zn and Mo is generally significantly lower from C-type bottom ash than from less weathered types of bottom ash. This reduction in leaching is due to the neutralisation of bottom ash pH and the formation of less soluble species of these elements as weathering continues. In the more weathered (C-type) bottom ash trace element leaching does not seem to be solubility-controlled; although slow precipitation reactions cannot be totally excluded, it is hypothesised that the controlling mechanism in those samples is sorption to neoformed minerals.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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sustainable stabilization solidification of municipal solid Waste Incinerator fly ash by incorporation of green materials
Journal of Cleaner Production, 2019Co-Authors: Liang Chen, Lei Wang, Dong Wan Cho, Daniel C W Tsang, Lizhi Tong, Yaoyu Zhou, Jian Yang, Chi Sun PoonAbstract:Abstract: Municipal solid Waste Incinerator fly ash (IFA) is categorized as a hazardous Waste, which requires proper treatment prior to landfilling due to its high concentrations of toxic elements. This study developed an innovative and cleaner method for stabilization/solidification (S/S) of IFA by the incorporation of supplementary cementitious materials (SCMs) and green stabilizers. Quantitative X-ray diffraction and thermogravimetric analyses indicated that toxic elements in IFA inhibited the cement hydration. Therefore, the single use of cement (10 wt%) was not efficient for the immobilization of toxic elements, especially for Pb. The incorporation of SCMs (20 wt% of binder) such as silica fume facilitated the formation of additional cement hydrates and reduced Pb leachability by 36.3%. The addition of green stabilizers such as potassium dihydrogen phosphate (KDP) and wood Waste-derived biochar also improved the immobilization of toxic elements. KDP directly combined with Pb2+ to form a precipitate of Pb3(PO4)2, whereas biochar promoted the generation of cement hydrates for S/S via the effect of internal curing. The incorporation of silica fume (40 wt%) in the binder was the most effective. Overall, this study demonstrated that the selected green binders can serve as low-carbon and high-efficient material for S/S of hazardous ash residue such as IFA.
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geochemical modeling and assessment of leaching from carbonated municipal solid Waste Incinerator mswi fly ash
Environmental Science and Pollution Research, 2016Co-Authors: Lei Wang, Imtiaz Ali Jamro, Qi Chen, Jingde LuanAbstract:Municipal solid Waste Incinerator (MSWI) fly ashes are characterized by high calcium oxide (CaO) content. Carbon dioxide (CO2) adsorption by MSWI fly ash was discussed based on thermogravimetry (TG)/differential thermal analysis (DTA), minerology analysis, and adapting the Stenoir equation. TG/DTA analysis showed that the weight gain of the fly ash below 440 °C was as high as 5.70 %. An adapted Stenoir equation for MSWI fly ash was discussed. The chloride in MSWI fly ash has a major impact on CO2 adsorption by MSWI fly ash or air pollution control (APC) residues. Geochemical modeling of the critical trace elements copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), and antimony (Sb) before and after carbonation was performed using a thermodynamic equilibrium model for solubility and a surface complexation model for metal sorption. Leaching of critical trace elements was generally found to be strongly dependent on the degree of carbonation attained, and their solubility appeared to be controlled by several minerals. Adsorption on ferrum (Fe) and aluminum (Al) colloids was also responsible for removal of the trace elements Cd, Pb, and Sb. We used Hakanson's potential ecological risk index (HPERI) to evaluate the risk of trace element leaching in general. The results demonstrate that the ecological risk showed a V-shaped dependency on pH; the optimum pH of the carbonated fly ash was found to be 10.3-11, resulting from the optimum carbonation (liquid-to-solid (L/S) ratio = 0.25, carbonation duration = ∼30-48 h). The dataset and modeling results presented here provide a contribution to assessing the leaching behavior of MSWI fly ash under a wide range of conditions.
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immobilization of trace elements in municipal solid Waste Incinerator mswi fly ash by producing calcium sulphoaluminate cement after carbonation and washing
Waste Management & Research, 2016Co-Authors: Lei Wang, Imtiaz Ali Jamro, Qi Chen, Jingde Luan, Tianhua YangAbstract:The possibility of producing calcium sulphoaluminate cement (CSA) by adding municipal solid Waste Incinerator (MSWI) fly ash to raw meal was investigated. After subjecting MSWI fly ash to accelerated carbonation and washing with water (ACW), various amounts (i.e., 5, 10 and 15 wt%) of the treated ash were added to raw meal composed of a mixture of bauxite, limestone and gypsum. The mixtures were sintered in a laboratory-scale muffle furnace at temperatures of 1250°, 1300°, 1325° and 1350 °C for various durations. The influence of different quantities of MSWI fly ash on the mineralogy, major phase composition and strength development of the resulting clinker was studied, as was the effect of ash treatments on leaching and volatilization of trace elements. The ACW treatment reduced the volatilization ratio of trace elements during the clinkerization process. Volatilization ratios for lead, cadmium and zinc were 21.5%, 33.6% and 16.3%, respectively, from the ACW fly ash treatment, compared with ratios of 97.5%, 93.1% and 85.2% from untreated fly ash. The volatilization ratios of trace elements were ordered as follows: untreated fly ash > carbonated fly ash > carbonated and water-washed fly ash. The ACW process also reduced the chloride content in the MSWI fly ash by 90 wt% and prevented high concentrations of trace elements in the effluents.
Kaelong Lin - One of the best experts on this subject based on the ideXlab platform.
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pozzolanic reactivity of the synthetic slag from municipal solid Waste Incinerator cyclone ash and scrubber ash
Journal of The Air & Waste Management Association, 2006Co-Authors: Kaelong Lin, Dengfong LinAbstract:Abstract Deng-Fong Lin is a professor in the Department of Civil and Ecological Engineering at IShou University in Taiwan, Republic of China.This study investigates the pozzolanic reactions and compressive strength of the blended cement manufactured using synthetic slag obtained from municipal solid Waste Incinerator (MSWI) cyclone ash and scrubber ash as partial replacement of portland cement. The synthetic slag was made by co-melting the MSWI scrubber ash and cyclone ash mixtures at 1400 °C for 30 min. Following pulverization, the different types of slag were blended with cement as cement replacement at ratios ranging from 10 to 40 wt %. The synthetic slag thus obtained was quantified, and the characteristics of the slag-blended cement pastes were examined. These characteristics included the pozzolanic activity, compressive strength, hydration activity, crystal phases, species, and microstructure at various ages. The 90-day compressive strength developed by slag-blended cement pastes with 10 and 20 wt %...
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the influence of municipal solid Waste Incinerator fly ash slag blended in cement pastes
Cement and Concrete Research, 2005Co-Authors: Kaelong LinAbstract:Vitrification technology can be used as an effective tool for immobilizing heavy metals into nonleachable slag. This technology involves subjecting the Waste material to high temperatures, so that the nonvolatile species become chemically bonded in the resultant matrix (slag), thereby becoming nonleachable. This study investigates the effect of mixing Type I, Type II, and Belite cements with municipal solid Waste Incinerator (MSWI) fly ash slag-blended cement (FASBC). The experimental results showed that replacement of 10-40% of the cement by slag caused an increase in the initial and the final setting time. The toxicity characteristic leaching procedure (TCLP) results show that the heavy metal content met the Environmental Protection Administration (EPA) regulatory limits. Compressive strength results indicate that the slag-blended cement (SBC) pastes had slower compressive strength development in the early stages, but this strength rebounded at later ages. Variations in the Portland cements can affect early strength development but have no significant effect on the degree of hydration at later ages. The degree of hydration of the slag decreased markedly with decreasing proportion of slags in the blend.
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hydraulic activity of cement mixed with slag from vitrified solid Waste Incinerator fly ash
Waste Management & Research, 2003Co-Authors: Kaelong Lin, K S Wang, B Y Tzeng, Chungyei LinAbstract:This study investigates the effects of the slag composition on the hydraulic activity in slag blended cement pastes that incorporate synthetic slag prepared by melting CaO-modified municipal solid Waste Incinerator fly ash. Two types of composition-modified slag were prepared for this study. First, fly ash was mixed with the modifier (CaO) at 5% and 15% (by weight) respectively, resulting in two fly ash mixtures. These mixtures were then melted at 1400 degrees C for 30 minutes and milled to produce two types of slag with different modifier contents, designated as C1-slag and C2-slag. These synthetic slags were blended with ordinary Portland cement at various weight ratios ranging from 10% to 40%. The synthetic slags presented sufficient hydraulic activity, and the heavy metal leaching concentrations all met the EPA's regulatory thresholds. The pore size distribution was determined by mercury intrusion porosimetry, and the results correlated with the compressive strength. The results also indicate that the incorporation of the 10% C1-slag tended to enhance the hydration degree of slag blended cement pastes during the early ages (3-28 days). However, at later ages, no significant difference in hydration degree was observed between ordinary Portland cement pastes and 10% C1-slag blended cement pastes. In the 10% C2-slag case, the trend was similar, but with a more limited enhancement during the early ages (3-28 days). Thus vitrified Waste Incinerator fly ash is a technically useful additive to cement, reducing the disposal needs for the toxic fly ash.
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hydraulic activity of municipal solid Waste Incinerator fly ash slag blended eco cement
Cement and Concrete Research, 2001Co-Authors: Kuensheng Wang, Kaelong Lin, Zuhquia HuangAbstract:Abstract The melting of municipal solid Waste Incinerator (MSWI) fly ash can produce an extremely stable glassy slag that exhibits pozzolanicity if activated. Such slag, therefore, could be recovered in more valuable form as a cement replacement than as a roadbed aggregate. This study investigates the hydraulic activity, compressive strength development, composition variation, and heavy metal leachability of such fly-ash-slag-blended cement (FASBC). The results indicate that FASBC pastes, with cement replacement ratios of less than 20%, show a smaller early strength but a larger later strength at the age of 28 days. It was found that early cement hydration, followed by the breakdown and dissolving of the slag, enhanced the formation of calcium silicate hydrates (C-S-H), which contributes to the later strength. The XRD and 29 Si MAS/NMR results also indicate that, after 28 days, both the hydration degree and the average length of the linear polysilicate anions would increase with an increasing cement replacement ratio, implying an increased strength development. On the other hand, the targeted heavy metal leaching concentrations in the synthetic slag and the FASBC paste were significantly low, thus clearing the EPA's regulatory thresholds. These factors suggest the feasibility and safety of using MSWI fly ash slag in blended cement.
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hydraulic activity of municipal solid Waste Incinerator fly ash slag blended eco cement
Cement and Concrete Research, 2001Co-Authors: K S Wang, Kaelong Lin, Zuhquia HuangAbstract:Abstract The melting of municipal solid Waste Incinerator (MSWI) fly ash can produce an extremely stable glassy slag that exhibits pozzolanicity if activated. Such slag, therefore, could be recovered in more valuable form as a cement replacement than as a roadbed aggregate. This study investigates the hydraulic activity, compressive strength development, composition variation, and heavy metal leachability of such fly-ash-slag-blended cement (FASBC). The results indicate that FASBC pastes, with cement replacement ratios of less than 20%, show a smaller early strength but a larger later strength at the age of 28 days. It was found that early cement hydration, followed by the breakdown and dissolving of the slag, enhanced the formation of calcium silicate hydrates (C-S-H), which contributes to the later strength. The XRD and 29 Si MAS/NMR results also indicate that, after 28 days, both the hydration degree and the average length of the linear polysilicate anions would increase with an increasing cement replacement ratio, implying an increased strength development. On the other hand, the targeted heavy metal leaching concentrations in the synthetic slag and the FASBC paste were significantly low, thus clearing the EPA's regulatory thresholds. These factors suggest the feasibility and safety of using MSWI fly ash slag in blended cement.
Zuhquia Huang - One of the best experts on this subject based on the ideXlab platform.
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hydraulic activity of municipal solid Waste Incinerator fly ash slag blended eco cement
Cement and Concrete Research, 2001Co-Authors: Kuensheng Wang, Kaelong Lin, Zuhquia HuangAbstract:Abstract The melting of municipal solid Waste Incinerator (MSWI) fly ash can produce an extremely stable glassy slag that exhibits pozzolanicity if activated. Such slag, therefore, could be recovered in more valuable form as a cement replacement than as a roadbed aggregate. This study investigates the hydraulic activity, compressive strength development, composition variation, and heavy metal leachability of such fly-ash-slag-blended cement (FASBC). The results indicate that FASBC pastes, with cement replacement ratios of less than 20%, show a smaller early strength but a larger later strength at the age of 28 days. It was found that early cement hydration, followed by the breakdown and dissolving of the slag, enhanced the formation of calcium silicate hydrates (C-S-H), which contributes to the later strength. The XRD and 29 Si MAS/NMR results also indicate that, after 28 days, both the hydration degree and the average length of the linear polysilicate anions would increase with an increasing cement replacement ratio, implying an increased strength development. On the other hand, the targeted heavy metal leaching concentrations in the synthetic slag and the FASBC paste were significantly low, thus clearing the EPA's regulatory thresholds. These factors suggest the feasibility and safety of using MSWI fly ash slag in blended cement.
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hydraulic activity of municipal solid Waste Incinerator fly ash slag blended eco cement
Cement and Concrete Research, 2001Co-Authors: K S Wang, Kaelong Lin, Zuhquia HuangAbstract:Abstract The melting of municipal solid Waste Incinerator (MSWI) fly ash can produce an extremely stable glassy slag that exhibits pozzolanicity if activated. Such slag, therefore, could be recovered in more valuable form as a cement replacement than as a roadbed aggregate. This study investigates the hydraulic activity, compressive strength development, composition variation, and heavy metal leachability of such fly-ash-slag-blended cement (FASBC). The results indicate that FASBC pastes, with cement replacement ratios of less than 20%, show a smaller early strength but a larger later strength at the age of 28 days. It was found that early cement hydration, followed by the breakdown and dissolving of the slag, enhanced the formation of calcium silicate hydrates (C-S-H), which contributes to the later strength. The XRD and 29 Si MAS/NMR results also indicate that, after 28 days, both the hydration degree and the average length of the linear polysilicate anions would increase with an increasing cement replacement ratio, implying an increased strength development. On the other hand, the targeted heavy metal leaching concentrations in the synthetic slag and the FASBC paste were significantly low, thus clearing the EPA's regulatory thresholds. These factors suggest the feasibility and safety of using MSWI fly ash slag in blended cement.
Miguel A Banares - One of the best experts on this subject based on the ideXlab platform.
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role of surface vanadium oxide coverage support on titania for the simultaneous removal of o dichlorobenzene and nox from Waste Incinerator flue gas
Catalysis Today, 2015Co-Authors: M Gallastegivilla, A Aranzabal, Zouhair Boukha, Jose A Gonzalezmarcos, Juan R Gonzalezvelasco, M V Martinezhuerta, Miguel A BanaresAbstract:Abstract The catalytic activity of VO x species supported on TiO 2 was investigated in the simultaneous destruction of NO and 1,2-dichlorobenzene (o-DCB), as typical pollutants molecules in the off-gases from municipal Waste Incinerator (MWI) plants. Catalysts with different vanadium loading were prepared in order to obtain different VO x species and characterized by ICP-AES, XPS, N 2 adsorption at −196 °C, XRD, H 2 -TPR, Raman and UV–vis–NIR DRS spectroscopy. The characterization results show that molecularly dispersed isolated and polymeric vanadia species form below the dispersion limit loading (“monolayer coverage”), while crystalline species form above it. We used moderate HNO 3 treatment to partially leach vanadium oxide species, creating a series of catalysts with variable vanadia loading. The catalytic activity of the VO x /TiO 2 catalyst shows that it is able to catalyze the destruction of both pollutants, although higher temperature is required for o-DCB oxidation than for NO reduction. Surface vanadia coverage has a clear effect on TOF and activation energy values, which underline that isolated vanadia species are more efficient for o-DCB oxidation, while the polymeric ones are more efficient for NO reduction.
