锰基水滑石固定修复U(Ⅵ)污染土壤的研究

Study on remediation of U(Ⅵ)-contaminated soil by manganese-based hydrotalcite

以水热法制备了二元水滑石(MnAl-LDH)和三元水滑石(MnMgAl-LDH),将其作为固定剂对U(Ⅵ)污染的土壤进行修复。利用毒性浸出实验(TCLP)和Tessier逐级化学提取法研究了固定前后铀的浸出特性与形态变化。结果表明,当含铀土壤不添加固定剂时,铀的浸出质量分数为147.20 mg/kg;当土壤中添加MnAl-LDH为固定剂培养28 d后,土壤中铀的浸出质量分数为44.16 mg/kg,浸出率为30.00%;投加MnMgAl-LDH培养28 d后,土壤中铀的浸出质量分数仅为31.90 mg/kg,浸出率降低至21.67%。

Binary hydrotalcite(MnAl-LDH) and ternary hydrotalcite(MnMgAl-LDH) are prepared by hydrothermal method, and used as fixative to remediate U(Ⅵ)-contaminated soil.The leaching characteristics and morphological changes of uranium before and after fixation are studied by means of toxic leaching experiment(TCLP) and Tessier step-by-step chemical extraction method.It is shown that the leaching concentration of uranium is 147.20 mg·kgwhen no fixative is added into the uranium-containing soil.The leaching concentration of uranium in the soil is 44.16 mg·kg,and the leaching rate is 30.00% when MnAl-LDH has been added into the soil for 28 days.The leaching concentration is only 31.90 mg·kgwith a leaching rate of 21.67% when MnMgAl-LDH is added.