Red mud-enhanced magnesium phosphate cement for remediation of Pb and As contaminated soil

Lei Wang, Liang Chen, Binglin Guo, Daniel C.W. Tsang, Longbin Huang, Yong Sik Ok, Viktor Mechtcherine

研究成果: ジャーナルへの寄稿学術誌査読

66 被引用数 (Scopus)


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·nH2O 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 MgKPO4·6H2O, 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.

ジャーナルJournal of Hazardous Materials
出版ステータス出版済み - 12月 5 2020

!!!All Science Journal Classification (ASJC) codes

  • 環境工学
  • 環境化学
  • 廃棄物管理と処理
  • 汚染
  • 健康、毒物学および変異誘発


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