Mechanistic insights into red mud, blast furnace slag, or metakaolin-assisted stabilization/solidification of arsenic-contaminated sediment

Lei Wang, Liang Chen, Daniel C.W. Tsang, Yaoyu Zhou, Jörg Rinklebe, Hocheol Song, Eilhann E. Kwon, Kitae Baek, Yong Sik Ok

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Elevated level of arsenic (As) in marine sediment via deposition and accumulation presents long-term ecological risks. This study proposed a sustainable stabilization/solidification (S/S) of As-contaminated sediment via novel valorization of red mud waste, blast furnace slag and calcined clay mineral, which were selected to mitigate the increased leaching of As under alkaline environment of S/S treatment. Quantitative X-ray diffraction and thermogravimetric analyses illustrated that stable Ca-As complexes (e.g., Ca5(AsO4)3OH) could be formed at the expense of Ca(OH)2 consumption, which inevitably hindered the hydration process and S/S efficiency. The 29Si nuclear magnetic resonance analysis revealed that incorporation of metakaolin for As immobilization resulted in a low degree of hydration and polymerization, whereas addition of red mud promoted Fe-As complexation and demonstrated excellent compatibility with As. Transmission electron microscopy and elemental mapping further confirmed the precipitation of crystalline Ca-As and amorphous Fe-As compounds. Therefore, red mud-incorporated S/S binder achieved the highest efficiency of As immobilization (99.9%), which proved to be applicable for both in-situ and ex-situ S/S of As-contaminated sediment. These results advance our mechanistic understanding for the design of green and sustainable remediation approach for effective As immobilization.

Original languageEnglish
Article number105247
JournalEnvironment International
Volume133
DOIs
Publication statusPublished - 2019 Dec

Keywords

  • Arsenic leachability
  • Green/sustainable remediation
  • Hydration and polymerization
  • Potentially toxic element
  • Precipitation chemistry
  • Waste valorization/recycling

ASJC Scopus subject areas

  • Environmental Science(all)

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