title: Geochemical modeling and assessment of leaching from carbonated municipal solid waste incinerator (MSWI) fly ash.
abstract: 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.
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China. wlei05@mails.tsinghua.edu.cn.|Chemical & Biological Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada. wlei05@mails.tsinghua.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China.
authors.forename: Imtiaz Ali
authors.initials: IA
authors.lastname: Jamro
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China.
authors.forename: Rundong
authors.initials: R
authors.lastname: Li
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China.
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China.
authors.forename: Shaobai
authors.initials: S
authors.lastname: Li
authors.affiliation: College of Energy & Environment, Shenyang Aerospace University, Shenyang, 110036, China.
authors.forename: Jingde
authors.initials: J
authors.lastname: Luan
mesh_terms: D000327:Adsorption; D000965:Antimony / Q000032:analysis; D017610:Calcium Compounds / Q000032:analysis; D002245:Carbon Dioxide / Q000737:chemistry; D057965:Carbon Sequestration; D002254:Carbonates / Q000032:analysis* / Q000737:chemistry; D002681:China; D060729:Coal Ash / Q000737:chemistry*; D003300:Copper / Q000032:analysis; D017745:Incineration / Q000379:methods*; D007501:Iron / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D008962:Models, Theoretical; D010087:Oxides / Q000032:analysis; D062611:Solid Waste / Q000032:analysis*; D012995:Solubility; D014131:Trace Elements / Q000032:analysis; D015032:Zinc / Q000032:analysis
chemical_list: D017610:Calcium Compounds; D002254:Carbonates; D060729:Coal Ash; D019216:Metals, Heavy; D010087:Oxides; D062611:Solid Waste; D014131:Trace Elements; D002245:Carbon Dioxide; D003300:Copper; D000965:Antimony; C016538:lime; D007501:Iron; D015032:Zinc
keywords: Accelerated carbonation; Ecological risk; Geochemical modeling; Leaching; MSWI fly ash; Trace element