title: Comparison of alternative remediation technologies for recycled gravel contaminated with heavy metals.
abstract: To evaluate the effects of different remediation methods on heavy metals contaminated recycled gravel, three immobilization agents (monopotassium phosphate, lime, nano-iron) and two mobilization agents (glyphosate, humic acid (HA)) were studied and compared. Results indicated that nano-iron powder was found to be more effective to immobilize Zn, Cu, Pb and Cd. Meanwhile, glyphosate presents a higher mobilization effect than HA with removal rates of about 66.7% for Cd, more than 80% for Cr, Cu and Zn, and the highest removal percentage of 85.9% for Cr. After the mobilization by glyphosate, the leaching rates of Zn, Cu and Cr were about 0.8%, and below 0.2% for Pb and Cd. The leaching rates after nano-iron powder treatment were 1.18% for Zn, 0.96% for Cr, 0.61% for Cu, 0.45% for Pb and Cd not detected. The formation and disappearance of metal (Zn/Cu/Cr/Pb/Cd) compounds were firmly confirmed through X-ray diffraction and scanning electron microscopy analyses on crystalline phases and morphological surface structures.
authors.affiliation: The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, P.R. China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Gao
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, P.R. China.
authors.forename: Yilu
authors.initials: Y
authors.lastname: Gu
authors.affiliation: The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, P.R. China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Huang
authors.affiliation: National Institute for Environmental Studies, Japan.
authors.forename: Guangyin
authors.initials: G
authors.lastname: Zhen
authors.affiliation: The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, P.R. China.
authors.forename: Guannan
authors.initials: G
authors.lastname: Deng
authors.affiliation: The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, P.R. China.
authors.forename: Tian
authors.initials: T
authors.lastname: Xie
authors.affiliation: The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, P.R. China zhaoyoucai@tongji.edu.cn.
authors.forename: Youcai
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D003252:Construction Materials / Q000032:analysis*; D004785:Environmental Pollutants / Q000032:analysis*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019216:Metals, Heavy / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D059027:Recycling; D018505:Waste Management; D014961:X-Ray Diffraction
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy
keywords: Contaminated recycled gravel; construction and demolition wastes; glyphosate; heavy metals; immobilization; mobilization