title: Leaching heavy metals in municipal solid waste incinerator fly ash with chelator/biosurfactant mixed solution.
abstract: The chelator [S,S]-ethylene diamine disuccinic acid, citric acid, and biosurfactant saponin are selected as leaching agents. In this study, the leaching effect of saponin mixed with either ethylene diamine disuccinic acid or citric acid on the levels of copper, zinc, lead, and cadmium in municipal solid waste incinerator fly ash is investigated. Results indicate that saponin separately mixed with ethylene diamine disuccinic acid and citric acid exhibits a synergistic solubilisation effect on copper, zinc, lead, and cadmium leaching from fly ash. However, saponin and ethylene diamine disuccinic acid mixed solution exhibits a synergistic solubilisation effect that is superior to that of a saponin and citric acid mixed solution. The extraction rate of heavy metal in fly ash leached with a saponin and chelator mixed solution is related to the pH of the leaching solution, and the optimal range of the pH is suggested to be approximately neutral. After leaching with a saponin and chelator mixed solution, copper, zinc, lead, and cadmium contents significantly decreased (p < 0.05) in the extractable or acid-soluble and reducible fractions. By adopting the proposed approach, the leaching concentrations of copper, zinc, lead, and cadmium in treated fly ash are in accordance with Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes GB18598-2001.
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes of Ministry of Education, Hohai University, Nanjing, China College of Environmental Engineering, Hohai University, Nanjing, China xyhohai@163.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.affiliation: College of Environmental Engineering, Hohai University, Nanjing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry; D060729:Coal Ash / Q000032:analysis*; D004784:Environmental Monitoring; D005029:Ethylenediamines / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis*; D012037:Refuse Disposal; D012503:Saponins / Q000737:chemistry; D062611:Solid Waste / Q000032:analysis*; D013386:Succinates / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: C499100:(S,S)-ethylenediaminedisuccinate; D002614:Chelating Agents; D060729:Coal Ash; D005029:Ethylenediamines; D019216:Metals, Heavy; D012503:Saponins; D062611:Solid Waste; D013386:Succinates; D013501:Surface-Active Agents; D019343:Citric Acid
keywords: Chelator; biosurfactants; fly ash; heavy metal; heavy metal form; leaching