title: Leaching of metals from cement under simulated environmental conditions.
abstract: Leaching of metals from cement under various environmental conditions was measured to evaluate their environmental safety. A cement product containing clinker, which was produced from cement kiln co-processing of hazardous wastes, was solidified and leaching of metals was characterized using the 8-period test. Concentrations and speciation of metals in cements were determined. Effects of ambient environment and particle size on leachability of metals and mineralogical phases of cement mortars were evaluated by use of XRD and SEM. Results indicated that metals in cements were leachable in various media in descending order of: sea water, groundwater and acid rain. Cr, Ni, As, Co and V were leached by simulated sea water, while Cu, Cd, Pb, Zn, Mn, Sb and Tl were not leached in simulated sea water, groundwater or acid rain. When exposed to simulated acid rain or groundwater, amounts of Cr, Ni, As and V leached was inversely proportional to particle size of cement mortar. According to the one-dimensional diffusion equation, Cr was most leachable and the cumulative leached mass was predicted to be 9.6 mg kg(-1) after 20 years. Results of this study are useful in predicting releases of metals from cement products containing ash and clinkers cement kiln co-processing of hazardous wastes, so that they can be safely applied in the environment.
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China.
authors.forename: Huixia
authors.initials: H
authors.lastname: Lu
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wei
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China. Electronic address: tangjch@nankai.edu.cn.
authors.forename: Jingchun
authors.initials: J
authors.lastname: Tang
authors.affiliation: Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; School of Biological Sciences, University of Hong Kong, Hong Kong, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China.
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
mesh_terms: D015258:Acid Rain; D000068476:Beijing; D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry; D006256:Hazardous Waste / Q000032:analysis*; D008670:Metals / Q000032:analysis* / Q000737:chemistry; D008962:Models, Theoretical; D010316:Particle Size; D012623:Seawater / Q000737:chemistry; D014876:Water Pollution / Q000032:analysis*
chemical_list: D015258:Acid Rain; D006256:Hazardous Waste; D008670:Metals
keywords: Exposed environment; Particle size; Speciation