Facile combinations of thiosulfate and zerovalent iron synergically immobilize cadmium in soils through mild extraction and facilitated immobilization

Maolin Wang; Canyang Hu; Jiahui Xu; Xudong Jing; Hafeez Ur Rahim; Xiyun Cai

doi:10.1016/j.jhazmat.2020.124806

Facile combinations of thiosulfate and zerovalent iron synergically immobilize cadmium in soils through mild extraction and facilitated immobilization

J Hazard Mater. 2021 Apr 5:407:124806. doi: 10.1016/j.jhazmat.2020.124806. Epub 2020 Dec 10.

Authors

Maolin Wang¹, Canyang Hu¹, Jiahui Xu¹, Xudong Jing¹, Hafeez Ur Rahim¹, Xiyun Cai²

Affiliations

¹ Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
² Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China. Electronic address: xiyuncai@dlut.edu.cn.

PMID: 33341570
DOI: 10.1016/j.jhazmat.2020.124806

Abstract

Cadmium (Cd) is one of the most toxic substances released in the environment. Cd-contaminated soils usually have a large pool of bioavailable Cd species and lead to excessive Cd accumulation in planted cereal crops. Treatment methods for stable immobilization of Cd in soils are desirable. Here we reported that facile combinations of thiosulfate (STS) and zerovalent iron (ZVI) reinforced Cd immobilization in soils and reduced Cd accumulation in wheat. STS mildly activated Cd in soils through the formation of soluble Cd(S₂O₃)_x complexes, whereas intermediates of STS (e.g., sulfate and sulfides) and ZVI synergically facilitated immobilization of Cd in soils. The synergy was ascribed to the facilitated formation of FeOOH with high Cd-binding affinity and formation of stable sulfate-Cd-FeOOH complexes and poorly available CdS_x. STS-ZVI treatments increased residual Cd in soils by 101-123% and decreased Cd accumulation in wheat shoots by 13-68%, depending on chemical compositions and doses of binary reagents. Field applications of STS and ZVI (0.06-0.11 kg/m²) demonstrated 24-39% reductions of grain Cd.

Keywords: Cadmium; Soil; Stabilization; Synergy; Wheat.

Publication types

Research Support, Non-U.S. Gov't