【摘要】 采用田间试验研究了改良剂（腐植酸）及由膨润土、硅藻土、氧化镁组配的钝化剂对土壤镉（Cd）的钝化效果及对土壤理化性质的影响,并借助红外光谱仪（FTIR）、扫描电镜联用能谱分析仪（SEM-EDS）和比表面分析仪（BET）,分析探讨了钝化改良剂对镉的钝化机理。结果表明:不同钝化改良剂处理初始有效态镉浓度为0.0836 mg/kg的菜地土壤70 d后,镉的钝化效率由高到低依次为:10 g/kg钝化剂+0.4 g/kg改良剂>10 g/kg钝化剂>5 g/kg钝化剂+0.4 g/kg改良剂>5 g/kg钝化剂>0.4 g/kg改良剂,其中10 g/kg钝化剂+0.4 g/kg改良剂对有效态镉的钝化效率达到60.2%。表征分析显示,钝化剂表面结构疏松,其表面的Na⁺、Ca²⁺、Mg²⁺等离子可与Cd²⁺发生离子交换反应,改良剂中含有醌基、醇羟基、羧基、羰基和C=C键,能与Cd²⁺发生配位络合作用,化学吸附是复配钝化改良剂降低土壤镉有效性的主要原因。更多还原

【Abstract】 The stabilizing effects of improved bentonite-diatomite-magnesia-humic acid composite curing agent on soil available Cd and its influence on soil physicochemical properties were investigated, and the related mechanisms were also studied by adopting FTIR, SEM-EDS and BET analyses. Results showed that after 70-day treatment, the concentration of available Cd in soil, which was initially 0.083 6 mg/kg, decreased significantly. The stabilizing efficiencies of different composite curing agents were in an order of 10 g/kg curing agent +0.4 g/kg humic acid > 10 g/kg curing agent > 5 g/kg curing agent + 0.4 g/kg humic acid> 5 g/kg curing agent > 0.4 g/kg humic acid. In particular, the stabilizing efficiency reached 60.2% for 10 g/kg curing agent + 0.4 g/kg humic acid treatment. SEM-EDS and BET analyses revealed that the curing agent exhibited loose surface structure, the existence of ions on the surface, which included Na⁺, Ca²⁺, Mg²⁺, could contribute to chemical adsorption through ion exchange.Besides, functional groups such as quinone, alcohol, hydroxyl, carboxyl, carbonyl and C=C bond in humic acid could coordinate with Cd²⁺. Chemical absorption is the main reason to reduce the availability of soil Cd.更多还原