Red mud-enhanced magnesium phosphate cement for remediation of Pb and As contaminated soil
- Authors
- Wang, Lei; Chen, Liang; Guo, Binglin; Tsang, Daniel C. W.; Huang, Longbin; Ok, Yong Sik; Mechtcherine, Viktor
- Issue Date
- 5-12월-2020
- Publisher
- ELSEVIER
- Keywords
- Contaminated soil remediation; Potentially toxic elements; Arsenic/lead leachability; Stabilization/solidification; Sustainable waste management; Synchrotron analysis
- Citation
- JOURNAL OF HAZARDOUS MATERIALS, v.400
- Indexed
- SCIE
SCOPUS
- Journal Title
- JOURNAL OF HAZARDOUS MATERIALS
- Volume
- 400
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/50845
- DOI
- 10.1016/j.jhazmat.2020.123317
- ISSN
- 0304-3894
- Abstract
- Lead (Pb) and arsenic (As) contaminated soil poses severe threats to human health. This study proposes a novel approach for synchronous stabilisation/solidification (S/S) of Pb and As contaminated soil and explains the immobilisation mechanisms in red mud-modified magnesium phosphate cement (MPC). Experimental results show that incorporation of red mud in MPC binder retarded over-rapid reaction and enhanced compressive strength via the formation of (Al,Fe,K)PO4 center dot nH(2)O compounds as indicated by X-ray diffractometer (XRD) and elemental mapping. The presence of Pb had a marginal effect on the MPC reaction; however, the presence of As suppressed the generation of MgKPO4 center dot 6H(2)O, leading to a significant delay of setting time and a reduction of compressive strength. Extended X-ray absorption fine structure (EXAFS) analysis proved that Pb2+ strongly coordinated with the PO43-, whereas AsO2- gently coordinated with K+. The MPC binder displayed an excellent immobilisation efficiency for Pb (99.9%), but was less effective for As. The use of red mud enhanced the As immobilisation efficacy to 80.5% due to strong complexation between AsO2- and Fe3+. The treated soils fulfilled requirements of metal(loid) leachability and mechanical strength for on-site reuse. Therefore, red mud-modified MPC can be an effective binder for sustainable remediation of Pb and As contaminated soil.
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Collections - College of Life Sciences and Biotechnology > Division of Environmental Science and Ecological Engineering > 1. Journal Articles
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