Zero-Valent Iron Nanoparticles Remediate Nickel-Contaminated Aqueous Solutions and Biosolids-Amended Agricultural Soil

Remediation on antimony-contaminated soil from mine area using zero-valent-iron doped biochar and their effect on the bioavailability of antimony

Due to the bioavailability and trophic web movement of antimony, the overexploitation of antimony mine resulted in antimony contamination that harmed the ecology nearby, raising concerns for public health. Whereas, most researches focused on the removal of antimony in the aqueous instead of the immobilization of antimony in the soil. Herein, the immobilized performance of biochar (BC) loaded with nano zero-valent iron (nZVI-BC) on antimony in the soil near the smelting area was researched through pot experiments for the first time, and its stabilization mechanism on antimony was investigated by valent state variation of antimony. The results demonstrated that BC restricted the cation exchange capacity and catalase activity in the soil. Whereas nZVI-BC had a favorable and negative impact on two variables, respectively. While the exchangeable speciation of antimony fell both from 15% to 2% after adding the BC and nZVI-BC, nZVI-BC showed more stable immobilization capacity on antimony over time than BC, whose exchangeable speciation only marginally rose (2% to 6%). The electron attraction force between nZVI-BC and antimony was also intensified owing to the oxidation-reduction process, which was considered as the stabilizing principle of nZVI-BC on antimony in soil. Furthermore, the decreased bioaccumulation factor for the perennial ryegrass (0.46 to 0.21) and Galinsoga parviflora Cav. (0.26 to 0.17) stated that the BC effectively mitigated the bioaccumulation risk of antimony.