EDTA在铅污染土壤治理中的优化处理方法

发布时间：2018-11-17 20:24

【摘要】：为了探究EDTA在土壤重金属污染治理中的优化处理方法,采用湿筛和水中重力沉降的方法,从人工Pb污染土壤(原土)中分离提取砂土、粉土和粘土,分析讨论了EDTA对土壤中Pb的去除效果,并从EDTA清洗前后土壤中Pb的BCR形态分布出发,分析了EDTA对不同粒径土壤中各形态Pb的去除效果。研究发现,实验用土壤中砂土、粉土和粘土含量分别为11.2%、75.6%和13.2%,EDTA浓度越高,土壤中Pb去除效果越好,且砂土中Pb最易被去除(~100%),粉土与原土其次(88.66%~96.50%),粘土最难被去除(64.78%~79.60%),但随着EDTA浓度增加,粒径对去除Pb的影响减弱。在土壤修复实践中,可通过利用不同浓度EDTA处理不同粒径土壤的方法达到优化效果。BCR形态分布说明外源性Pb进入土壤后主要以弱酸提取态和可还原态存在,EDTA清洗主要去除弱酸提取态和可还原态,粘土中的各形态去除率均最小。
[Abstract]:In order to explore the optimal treatment method of EDTA in soil heavy metal pollution treatment, sand soil, silt soil and clay were separated and extracted from artificial Pb contaminated soil (original soil) by wet sieve and gravity sedimentation in water. The removal effect of EDTA on Pb in soil was discussed. Based on the BCR speciation distribution of Pb in soil before and after EDTA cleaning, the removal effect of EDTA on Pb in soil with different particle size was analyzed. The results showed that the higher the concentration of sand, silt and clay were 11.2and 13.2EDTA, the better the removal of Pb in soil, and the easier the removal of Pb was (~ 100%) in sandy soil. Silt and raw soil were next (88.66%), clay was the most difficult to be removed (64.78%), but with the increase of EDTA concentration, the effect of particle size on Pb removal was weakened. In the practice of soil remediation, the optimal results could be achieved by using different concentrations of EDTA to treat soil with different particle sizes. The speciation distribution of BCR indicated that exogenous Pb mainly existed as weak acid extractable state and reducible state after entering the soil. EDTA cleaning is mainly used to remove the weak acid extractable state and the reducible state, and the removal rate of each form in clay is the lowest.
【作者单位】：中设设计集团股份有限公司;江苏省交通运输环境保护工程技术中心;河海大学环境学院;
【基金】：江苏省交通科学研究计划项目(2013Y16) 江苏省太湖水污染治理专项(TH2013212)
【分类号】：X53

【相似文献】