MIL-101(Fe) based biomass as permeable reactive barrier applied to EK-PRB remediation of antimony contaminated soil

Numerous studies have demonstrated that electrokinetic-permeable reactive barrier (EK-PRB) can be used for the remediation of heavy metal contaminated soils, and their remediation efficiency is mainly determined by the filler material selected. By growing MIL-101(Fe) in situ on hollow loofah fiber (HLF), a novel material entitled HLF@MIL-101(Fe) was developed. The morphological characteristics and loading conditions were investigated, the adsorption characteristics were analyzed, and finally the synthesized composite material was applied to treat antimony-contaminated soil with EK-PRB as the reaction medium. The results show that MIL-101(Fe) is stably loaded on HLF. The adsorption capacity of Sb(III) can reach up to 82.31 mg g−1, and the adsorption is in accordance with the quasi-secondary kinetic model, which indicates that chemisorption is dominant. The isothermal adsorption model indicates that the adsorption form of HLF@MIL-101(Fe) is mainly monolayer adsorption with more uniform adsorption binding energy. In the EK-PRB experiment, when ethylenediaminetetraacetic acid (EDTA) is used as the cathodic electrolyte, it can effectively enhance the electromigration and electroosmotic effects, and the overall remediation efficiency of the soil is increased by 38.12% compared with the citric acid (CA) group. These demonstrate the feasibility of HLF@MIL-101(Fe) in collaboration with EK-PRB in the treatment of antimony-contaminated soil.