摘要
Fe–Mn binary oxide(FMBO) possesses high efficiency for As(Ⅲ) abatement based on the good adsorption affinity of iron oxide and the oxidizing capacity of Mn(Ⅳ), and the composition and structure of FMBO play important roles in this process.To compare the removal performance and determine the optimum formula for FMBO, magnetic graphene oxide(MRGO)–FMBO and MRGO–MnO2 were synthesized with MRGO as a carrier to improve the dispersity of the adsorbents in aquifers and achieve magnetic recycling.Results indicated that MRGO–FMBO had higher As(Ⅲ) removal than that of MRGO–MnO2,although the ratios of Fe and Mn were similar, because the binary oxide of Fe and Mn facilitated electron transfer from Mn(Ⅳ) to As(Ⅲ), while the separation of Mn and Fe on MRGO–MnO2 restricted the process.The optimal stoichiometry x for MRGO–FMBO(MnxFe3-xO4) was 0.46, and an extraordinary adsorption capacity of 24.38 mg/g for As(Ⅲ) was achieved.MRGO–FMBO showed stable dispersive properties in aquifers, and exhibited excellent practicability and reusability, with a saturation magnetization of 7.6 emu/g and high conservation of magnetic properties after 5 cycles of regeneration and reuse.In addition, the presence of coexisting ions would not restrict the practical application of MRGO–FMBO in groundwater remediation.The redox reactions of As(Ⅲ) and Mn(Ⅳ) on MRGO–FMBO were also described.The deprotonated aqueous As(Ⅲ) on the surface of MRGO–FMBO transferred electrons to Mn(Ⅳ), and the formed As(Ⅴ) oxyanions were bound to ferric oxide as inner-sphere complexes by coordinating their "–OH" groups with Mn(Ⅳ)oxides at the surface of MRGO–FMBO.This work could provide new insights into highperformance removal of As(Ⅲ) in aquifers.
Fe–Mn binary oxide（FMBO） possesses high efficiency for As（Ⅲ） abatement based on the good adsorption affinity of iron oxide and the oxidizing capacity of Mn（Ⅳ）, and the composition and structure of FMBO play important roles in this process.To compare the removal performance and determine the optimum formula for FMBO, magnetic graphene oxide（MRGO）–FMBO and MRGO–MnO2 were synthesized with MRGO as a carrier to improve the dispersity of the adsorbents in aquifers and achieve magnetic recycling.Results indicated that MRGO–FMBO had higher As（Ⅲ） removal than that of MRGO–MnO2,although the ratios of Fe and Mn were similar, because the binary oxide of Fe and Mn facilitated electron transfer from Mn（Ⅳ） to As（Ⅲ）, while the separation of Mn and Fe on MRGO–MnO2 restricted the process.The optimal stoichiometry x for MRGO–FMBO(MnxFe3-xO4) was 0.46, and an extraordinary adsorption capacity of 24.38 mg/g for As（Ⅲ） was achieved.MRGO–FMBO showed stable dispersive properties in aquifers, and exhibited excellent practicability and reusability, with a saturation magnetization of 7.6 emu/g and high conservation of magnetic properties after 5 cycles of regeneration and reuse.In addition, the presence of coexisting ions would not restrict the practical application of MRGO–FMBO in groundwater remediation.The redox reactions of As（Ⅲ） and Mn（Ⅳ） on MRGO–FMBO were also described.The deprotonated aqueous As（Ⅲ） on the surface of MRGO–FMBO transferred electrons to Mn（Ⅳ）, and the formed As（Ⅴ） oxyanions were bound to ferric oxide as inner-sphere complexes by coordinating their "–OH" groups with Mn（Ⅳ）oxides at the surface of MRGO–FMBO.This work could provide new insights into highperformance removal of As（Ⅲ） in aquifers.
基金
supported by the National Natural Science Foundation of China(Nos.41772244,41530636 and 41977158)
111 Project(No.B16020)
Graduate Innovation Fund of Jilin University(No.2017074)
Jilin provincial education department “the 13th five-year” science and technology project(No.JJKH20180165KJ)
Jilin province development and reform commission project(No.2019C0553)
the Fundamental Research Funds for the Central Universities and China Scholarship Council(No.201806175055).
作者简介
Corresponding author:Zifang Chi,E-mail:chizifang@jlu.edu.cn;Tao Sha,E-mail:shatao@baohangenv.com
