Diphenylarsinic acid(DPAA)is both the prime starting material and major metabolite of chemical weapons(CWs).Because of its toxicity and the widespread distribution of abandoned CWs in burial site,DPAA sorption by natural Fe minerals is of considerable interest.Here we report the first study on DPAA sorption by natural magnetite and siderite using macroscopic sorption kinetics,sequential extraction procedure(SEP)and microscopic extended X-ray absorption fine-structure spectroscopy(EXAFS).Our results show that the sorption pseudo-equilibrated in 60 minutes and that close to 50％ and 20％-30％ removal can be achieved for magnetite and siderite,respectively,at the initial DPAA concentrations of 4-100 mg/L.DPAA sorption followed pseudo-secondary and intra-particle diffusion kinetics models,and the whole process was mainly governed by intra-particle diffusion and chemical bonding.SEP and EXAFS results revealed that DPAA mainly formed inner-sphere complexes on magnetite(＞80％),while on siderite it simultaneously resulted in outer-sphere and inner-sphere complexes.EXAFS analysis further confirmed the formation of inner-sphere bidentate binuclear corner-sharing complexes(2C)for DPAA.Comparison of these results with previous studies suggests that phenyl groups are likely to impact the sorption capacity and structure of DPAA by increasing steric hindrance or affecting the way the central arsenic(As)atom maintains charge balance.These results improve our knowledge of DPAA interactions with Fe minerals,which will help to develop remediation technology and predict the fate of DPAA in soil-water environments.

School of Ecology and Environment,Anhui Normal University,Wuhu 241002,China;Key Laboratory of Coastal Environmental Processes and Ecological Remediation,Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences,Yantai 264003,China;Anhui Provincial Engineering Laboratory of Water and Soil Pollution Control and Remediation,Anhui Normal University,Wuhu 241002,China;Center of Cooperative Innovation for Recovery and Reconstruction of Degraded Ecosystem in Wanjiang City Belt,Anhui Normal University,Wuhu 241002,China;Key Laboratory of Soil Environment and Pollution Remediation,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China

[1]Meng Zhu;Yuhuan He;Xiaobao Wei;Haoran Qi;Yunpeng Zhang;Yijun Zhang;Ruyi Yang;Yongming Luo-.Sorption mechanisms of diphenylarsinic acid on natural magnetite and siderite:Evidence from sorption kinetics,sequential extraction and extended X-ray absorption fine-structure spectroscopy analysis)[J].环境科学与工程前沿,2022(09):39-52

diphenylarsinic,Diphenylarsinic,DPAA,CWs

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