Abstract：
The migration and transformations of Cd and As in soil are different, so it is difficult to simultaneously control them. In this study, an organo-mineral complex (OMC) material was prepared using modified palygorskite and chicken manure, the Cd and As adsorption capacities and mechanism of the OMC were explored, and the response of the crop to the OMC was clarified. The results show that the maximum Cd and As adsorption capacities of the OMC under pH values of 6-8 are 12.19 mg·g-1 and 5.07 mg·g-1, respectively. In the OMC system, the modified palygorskite contributed more to the adsorption of the heavy metals than the organic matter. Cd2+ may form CdCO3 and CdFe2O4, and AsO2- may form FeAsO4, As2O3, and As2O5 on the surfaces of the modified palygorskite. Organic functional groups such as hydroxyl, imino, and benzaldehyde groups can participate in the adsorption of Cd and As. The Fe species and carbon vacancy in the OMC system promote the conversion of As3+ into As5+. A laboratory experiment was conducted to compare five commercial remediation agents with OMC. Planting Brassica campestris in the OMC remediated soil with excessive contamination increased the crop biomass and decreased the Cd and As accumulation sufficiently to meet the current national food safety standards. This study emphasizes the effectiveness of OMC in preventing the migration of Cd and As into crops while promoting crop growth, which can provide a feasible soil management strategy for CdAs co-contaminated farmland soil.
摘要：
Cd和As在土壤中的迁移和转化是不同的，所以很难同时控制它们。在这项研究中,使用改性坡缕石和鸡粪制备了有机矿物复合物（OMC）材料，探讨了OMC对Cd和As的吸附能力和机理，并阐明了作物对OMC的反应。结果表明，在pH值为6-8时，OMC对Cd和As的最大吸附量分别为12.19mg·g-1和5.07mg·g-1。在OMC系统中,改性坡缕石对重金属的吸附作用大于对有机物的吸附作用。在改性坡缕石的表面上，Cd2可以形成CdCO3和CdFe2O4，AsO2-可以形成FeAsO4，As2O3和As2O5。有机官能团如羟基，imino,苯甲醛基团可以参与Cd和As的吸附。OMC系统中的Fe物种和碳空位促进了As3+向As5+的转化。进行了实验室实验，以比较五种商业修复剂与OMC。在污染过多的OMC修复土壤中种植油菜可以增加作物生物量，并减少Cd和As的积累，以满足当前的国家食品安全标准。这项研究强调了OMC在防止Cd和As迁移到作物中，同时促进作物生长的有效性。为CdAs共污染农田土壤提供可行的土壤管理策略。
