Title: Factors affecting the leaching behaviours of magnesium phosphate cement-stabilised/solidified Pb-contaminated soil, part 1: water-to-solid ratio and Pb concentration

Authors: Ping Wang; Qiang Xue; Jiang-Shan Li; Ting-Ting Zhang; Shan-Yong Wang; Zhen-Ze Li; Lei Liu

Addresses: State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China ' Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, 430071, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China ' State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China ' State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China ' ARC Centre of Excellence for Geotechnical Science and Engineering, The University of Newcastle Callaghan, NSW 2308, Australia ' State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China ' State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China

Abstract: Magnesium phosphate cement (MPC) is widely used to effectively stabilise/solidify heavy-metal-contaminated soils, and leachability is the most important parameter for MPC-treated metal-contaminated soil. However, various factors in the stabilisation/solidification (S/S) process, such as the metal concentration in the soil and the water-to-solid (W/S) ratio of the S/S paste treated using MPC, can greatly affect the leaching behaviour of heavy metal in S/S monolith. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching tests were conducted to investigate the effects of metal concentrations and W/S ratios on the leaching behaviours of MPC treated Pb contaminated soil. Results showed that the Pb concentration and W/S ratios change the leaching behaviours and leaching mechanisms of MPC-treated Pb-contaminated soil and the optimum W/S ratio 0.50 was obtained when MPC was used to stabilise Pb contaminated soils.

Keywords: stabilisation/solidification; leaching behaviour; water-to-solid ratio; magnesium phosphate cement; MPC.

DOI: 10.1504/IJEP.2018.093027

International Journal of Environment and Pollution, 2018 Vol.63 No.1/2, pp.89 - 103

Accepted: 18 Nov 2017
Published online: 26 Jun 2018 *

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