Simultaneous Mitigating the Bioavailability of Cadmium and Arsenic in Paddy Soil by Two Carbon-Iron Composites: A Field-Scale Evaluation

作     者：Chen, Gongning Liang, Zihao Liang, Yanpeng Zhou, Zijian Lu, Yuxi Li, Huawei Zeng, Honghu 

作者机构：College of Environmental Science and Engineering Guilin University of Technology Guilin541004 China Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology Guilin University of Technology Guilin541004 China Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Areas Guilin University of Technology Guilin541004 China 

出 版 物：《SSRN》 

年 卷 期：2023年

核心收录：

主　　题：Cadmium 

摘      要：Cadmium (Cd) and arsenic (As) have become the focus and difficulty of inorganic pollution control in rice fields due to their opposite chemical properties, distinct geochemical behavior and wide distribution. Field experiments were performed to thoroughly evaluate the performance and mechanism of the two carbon-iron compositesin(ZVI-biochar and ZVI-peat) mitigating the bioavailability of soil Cd and As. The results indicated that the mitigating performance for Cd bioavailability decreased as follows: ZVI-biochar ZVI-peat biochar wood peat ZVI, and the mitigating performance for As bioavailability was in the order of ZVI-peat ZVI-biochar ZVI;Biochar and wood peat enhanced the bioavailability of soil As. The two Carbon-iron composites signifificantly decreased Cd(65.6-81.6%) and As(at least 32%) concentration in soil solution and bioavailable soil Cd and As forms compared with the control. Both ZVI-biochar and ZVI-peat resulted in a more than 42% reduction for grain Cd and 33.8% reduction for grain As. The two carbon-iron composites demonstrated synergistic effects of carbon materials and ZVI by facilitating the transformation Cd and As from bioavailable fractions to immobilized fractions, which was attribute to carbon materials’ electrical conductivity that lead to rapid corrosion of ZVI and generation of amorphous iron oxyhydroxides and iron-based ternary complexes. Nevertheless, the two carbon-iron composites achieved a higher soil pH, CEC and the formation of iron plaque in rice rhizosphere than single carbon materials or ZVI treatments, thus showed superior immobilization performance. In addition, the two carbon-iron composites significantly enhanced the Fe availability and promoted Fe uptake in rice tissues, which inhibited the Cd/As transported from rice roots to grains and mitigated Cd/As uptake in rice grains. Therefore, the two carbon-iron composites showed great potential toward sustainability in situ synchronous amelioration and safe utilizatio