Mechanochemical immobilization of lead contaminated soil by ball milling with the additive of Ca(H2PO4)2

Ziwei Zhang; Wenyi Yuan; Peizhong Li; Qingbin Song; Xiaoyan Wang; Weitong Xu; Xuefeng Zhu; Qiwu Zhang; Jianwei Yue; Jianfeng Bai; Jingwei Wang

doi:10.1016/j.chemosphere.2020.125963

Mechanochemical immobilization of lead contaminated soil by ball milling with the additive of Ca(H₂PO₄)₂

Chemosphere. 2020 May:247:125963. doi: 10.1016/j.chemosphere.2020.125963. Epub 2020 Jan 20.

Authors

Ziwei Zhang¹, Wenyi Yuan², Peizhong Li³, Qingbin Song⁴, Xiaoyan Wang⁵, Weitong Xu⁶, Xuefeng Zhu⁷, Qiwu Zhang⁸, Jianwei Yue⁹, Jianfeng Bai¹⁰, Jingwei Wang¹¹

Affiliations

¹ School of Environmental and Materials Engineering, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: ziwei8208@sina.com.
² Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: wyyuan@sspu.edu.cn.
³ Beijing Key Laboratory of Industrial Land Contamination and Remediation, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China. Electronic address: liepi_li@163.com.
⁴ Macau Environmental Research Institute, Macau University of Science and Technology, Macau, Macao. Electronic address: qbsong@must.edu.mo.
⁵ School of Environmental and Materials Engineering, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: wangxy@sspu.edu.cn.
⁶ School of Environmental and Materials Engineering, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: ab8260050@qq.com.
⁷ School of Environmental and Materials Engineering, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: xfzhu@sspu.edu.cn.
⁸ School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, China. Electronic address: Zhangqw@whut.edu.cn.
⁹ Shanxi Unisdom Testing Technology Co., Ltd. Shanxi, 030006, China. Electronic address: yuejianwei168@163.com.
¹⁰ Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: jfbai@sspu.edu.cn.
¹¹ Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: jwwang@sspu.edu.cn.

PMID: 32069729
DOI: 10.1016/j.chemosphere.2020.125963

Abstract

Lead (Pb) pollution in the soil is becoming more and more serious, and lead poisoning incidents also constantly occur. Therefore, the remediation of lead pollution in the soil has attracted widespread attention. In this study, heavy metal lead in soil was remediated by mechanochemical methods. The effects of different ball milling conditions on the toxic leaching concentration and morphological distribution (BCR sequential extraction procedure) of lead in contaminated soil were analyzed, including the addition of calcium dihydrogen phosphate (Ca(H₂PO₄)₂), ball milling time, and ball milling speed. The reaction mechanism was analyzed by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and a laser particle size analyzer. The results show that the optimal conditions for mechanochemical immobilization were 10% additive (Ca(H₂PO₄)₂), milling speed of 550 rpm, and ball milling time for 2 h. Under this condition, the toxic leaching concentration of lead from contaminated soil was 4.36 mg L^-1, and in the BCR sequential extraction procedure, Pb was mainly present in the residual fraction (54.96%). The mechanism of mechanochemical solidification of heavy metal lead in soil is that, during the ball milling process, the lead precipitates with Ca(H₂PO₄)₂ to produce dense agglomerates (Pb₃(PO₄)₂ and Pb_xCa_10-x(PO₄)₆(OH)₂), which fixes the lead in the soil and hampers its leaching.

Keywords: Immobilization; Lead contaminated soil; Mechanochemical ball milling.

MeSH terms

Calcium Phosphates / chemistry*
Calcium Pyrophosphate / chemistry
Chemical Precipitation
Environmental Restoration and Remediation / methods*
Lead / chemistry
Lead / isolation & purification*
Metals, Heavy / chemistry
Metals, Heavy / isolation & purification
Microscopy, Electron, Scanning
Soil Pollutants / analysis
Soil Pollutants / chemistry*
Soil Pollutants / isolation & purification

Substances

Calcium Phosphates
Metals, Heavy
Soil Pollutants
Lead
Calcium Pyrophosphate