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| Characterization of adsorption-desorption of diphenylarsenic acid in soil mediated by sulfate-reducing bacteria |
| Received:June 06, 2024 |
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| KeyWord:Diphenylarsinic acid（DPAA）;sulfate reducing bacteria;adsorption and desorption;iron reduction;sulfate reduction |
| Author Name | Affiliation | E-mail | | XING Qianwen | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
School of Geographical Sciences, Hunan Normal University, Changsha 410081, China | | | LU Lulu | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
School of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China | | | TU Chen | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China | ctu@issas.ac.cn | | LIU Ying | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China | | | LUO Runlai | CSCEC Eco-Environmental Engineering Research Center (Soil Remediation Technology and Equipment), China Construction Eighth Engineering Division Co., Ltd., Shanghai 200444, China | | | LI Zhongyuan | CSCEC Eco-Environmental Engineering Research Center (Soil Remediation Technology and Equipment), China Construction Eighth Engineering Division Co., Ltd., Shanghai 200444, China | | | LUO Yongming | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China | |
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| Abstract: |
| This study explores the adsorption-desorption kinetics of diphenylarsinic acid（DPAA）in ferrihydrite and black soil mediated by sulfate-reducing bacteria（Clostridium sp. SRB-2）, and clarifies the coupling mechanism of DPAA with sulfur and iron cycles in ferrihydrite and soil mediated by SRB-2. In this study, DPAA was selected as the target pollutant. Black soil, the predominant soil type inthe Japanese chemical weapon burial areas, was used as the test soil. Ferrihydrite, the principal iron mineral in the black soil, was chosen as the test iron mineral, and the sulfate-reducing bacterium（Clostridium sp. SRB-2）was used as the test strain. Using HPLC-MS/MS, we found that in the adsorption experiments, the ferrihydrite with SRB-2 inoculation significantly decreased the DPAA adsorption compared to the non-inoculated control group after 8 hours since the experiment started, while in the black soil system, the adsorption capacity of DPAA increased along with the culture time. In addition, the adsorption capacity of DPAA in the SRB-2 inoculation group was significantly lower than that of the control within 24 h. In the desorption experiments, inoculation with SRB-2 promoted the release of DPAA from ferrihydrite and black soil. The strain SRB-2 increased pH to around 7.0, decreased the concentrations of sulfate ions to 1 571 mg·L-1 and 1 425 mg·L-1, and reduced the redox potential to -263 mV and -352 mV. These changes enhanced the reduction of iron oxides （to >80% and >90% of the total iron）, thereby leading to the release of DPAA. The main transformation product was diphenylthioarsinic acid（DPTAA）. The study indicated that inoculation of Clostridium sp. SRB-2 could promote sulfate reduction to generate highly reductive sulfides. These sulfides, in turn, caused the reductive dissolution of iron oxides in the soil system, leading to the release of DPAA adsorbed on the soil solid phase surface into the solution environment, thus facilitating the transformation of DPAA mediated by SRB-2. |
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