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  3. Performance of chemical chelating agent stabilization and cement solidification on heavy metals in MSWI fly ash: A comparative study

Performance of chemical chelating agent stabilization and cement solidification on heavy metals in MSWI fly ash: A comparative study

  • J Environ Manage. 2019 Oct 1;247:169-177. doi: 10.1016/j.jenvman.2019.06.089.
Wenchao Ma 1,  Dongmei Chen 2,  Minhui Pan 2,  Tianbao Gu 2,  Lei Zhong 3,  Guanyi Chen 4,  Beibei Yan 2,  Zhanjun Cheng 2
Affiliations

Affiliations

  • 1 Tianjin Engineering Research Center of Bio Gas/Oil Technology, State Key Laboratory of Engines, School of Environmental Science and Engineering, Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, Ministry of Education, Tianjin University, Tianjin 300072, China. Electronic address: mawc916@tju.edu.cn.
  • 2 Tianjin Engineering Research Center of Bio Gas/Oil Technology, State Key Laboratory of Engines, School of Environmental Science and Engineering, Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, Ministry of Education, Tianjin University, Tianjin 300072, China.
  • 3 Tianjin Engineering Research Center of Bio Gas/Oil Technology, State Key Laboratory of Engines, School of Environmental Science and Engineering, Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, Ministry of Education, Tianjin University, Tianjin 300072, China. Electronic address: lei.zhong@tju.edu.cn.
  • 4 School of Science, Tibet University, Lhasa, 850012, China. Electronic address: chen@tju.edu.cn.
PMID: 31247364 DOI: 10.1016/j.jenvman.2019.06.089
Abstract

Heavy metal stabilization by chemical chelating agent and solidification by cement are technologies currently used to reduce the leaching of heavy metals in municipal solid waste incineration (MSWI) fly ash. This paper studied the physico-chemical properties of the fly ash, heavy metals content in the fly ash, and the leaching concentration of the heavy metals from fly ash. The effect of four Chelating Agents namely dithiocarbamate (1#), dithiocarbamic acid dipotassium salt (2#), amino dithiocarbamate chelating resin (3#) and thiourea (4#) on the stabilization and leaching of heavy metals were investigated. Different addition ratios (1%, 2% and 3% w/w) of the Chelating Agents, various curing time (7, 14, 28 days), and different amounts of the cement (10%, 15% and 20% w/w) were used in order to find the agent with the optimum stabilization and leaching of heavy metals as well as find the effect of combining the agent and cement. The results showed that the dithiocarbamate (1#) chelating agent had the best stabilizing performance due to the three-dimensional structure after their reaction. The addition of cement to the fly ash led to the immobilization of heavy metals due to the C-S-H gel formation. The technology of cement solidification and chelating agent stabilization was optimal from the point of economic cost and the complexity aspect.

Keywords

Cement; Chemical chelating agent; Fly ash; Heavy metals; Stabilization/solidification (S/S).

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