土壤电荷特性对NH_(4)-D树脂修复铀污染土壤的研究

Effect of soil charge characteristics on remediation ofuranium contaminated soil with NH_(4)-D resin

为解决铀尾矿库中铀元素迁移污染周围环境的问题,采用氨基磷酸螯合树脂D418制备出NH_(4)-D材料,通过表面电荷特性实验、毒性浸出实验和形态分析实验,考察了铀污染土壤固化效果与土壤电荷变化之间的关系。结果表明,土壤中铀的固定效率和电荷变化受土壤pH、固定剂投加量(n)的影响。随pH和投加量(n)的增加,固化后土壤表面负电荷数增大,电荷密度增强,在pH=5和n=6%时,出现铀最佳固定效率83.67%、最大负电位(φ)=-17.345 mV和最大负电荷密度(SCN)=1.142 cmol/kg;与CK组对比,NH_(4)-D增强了土壤中铀由不稳定的可交换态向稳定的残渣态转换。NH_(4)-D表现出对污染土壤中U(Ⅵ)有较好的固定和富集效果。

In order to solve the problem of uranium migration in uranium tailings pond polluting the surrounding environment,NH_(4)-D material was prepared by using amino phosphate chelating resin D418.The relationship between the solidification effect of uranium contaminated soil and the change of soil charge was investigated through surface charge characteristics experiment,toxicity leaching experiment and speciation analysis experiment.The results show that the fixation efficiency and charge change of uranium in soil are affected by soil pH and the dosage of fixative n.With the increase of pH and dosage of n,the negative charge number and charge density of the solidified soil surface increase,and the optimal uranium fixation efficiency and maximum negative potential appear at pH=5 and n=6%,φ=-17.345 mV and maximum negative charge density SCN=1.142 cmol/kg;compared with CK group,NH_(4)-D enhanced the transformation of uranium in soil from unstable exchangeable state to stable residual state.NH_(4)-D Showed good fixation and enrichment effect on U(Ⅵ)in contaminated soil.