While the transformation of antimony (Sb) in paddy soil has been previously investigated,the biogeochemical processes of highly chemical active Sb in the soil remain poorly under-stood.In addition,there is a lack of quantitative understanding of Sb transformation in soil.Therefore,in this study,the kinetics of exogenous Sb in paddy soils were investigated under anaerobic and aerobic incubation conditions.The dissolved Sb(Ⅴ) and the Sb(Ⅴ) extracted by diffusive gradient technique decreased under anaerobic conditions and then increased un-der aerobic conditions.The redox reaction of Sb occurred,and Sb bioavailability significantly decreased after 55 days of incubation.The kinetics of Fe and the scanning transmission elec-tron microscopy analysis revealed that the Fe oxides were reduced and became dispersed under anaerobic conditions,whereas they were oxidized and re-aggregated during the aer-obic stage.In addition,the redox processes of sulfur and nitrogen were detected under both anaerobic and aerobic conditions.Based on these observations,a simplified kinetic model was established to distinguish the relative contributions of the transformation processes.The bioavailability of Sb was controlled by immobilization as a result of S reduction and by mobilization as a result of Fe reductive dissolution and S oxidation,rather than the pH.These processes coupled with the redox reaction of Sb jointly resulted in the complex behav-ior of Sb transformation under anaerobic and aerobic conditions.The model-based method and findings of this study provide a comprehensive understanding of the Sb transformation in a complex soil biogeochemical system under changing redox conditions.

Bingqing Xia;Yang Yang;Fangbai Li;Tongxu Liu

Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China;National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China,Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management,Institute of Eco-environmental and Soil Sciences,Guangdong Academy of Sciences,Guangzhou 510650,China;University of Chinese Academy of Sciences,Beijing 100049,China

环境科学学报（英文版）

[1]Bingqing Xia;Yang Yang;Fangbai Li;Tongxu Liu-.Kinetics of antimony biogeochemical processes under pre-definite anaerobic and aerobic conditions in a paddy soil)[J].环境科学学报（英文版）,2022(03):269-280

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