六价铬污染土壤还原稳定修复

Reduction and Stabilization Remediation of Hexavalent Chromium Contaminated Soil

以常州某关闭化工厂遗留的铬污染土壤为研究对象,利用还原-稳定固化法对铬污染土壤进行修复,通过不同的单因子试验研究,确定最佳还原剂及优化条件,同时优化稳定固化条件,降低药剂成本。实验结果表明:选用酸化硫酸亚铁为还原剂,石灰为固化剂,联合使用,能够有效降低土壤中六价铬的浓度,其Cr(Ⅵ)去除率达到98%以上;Cr(Ⅵ)、总Cr毒性浸出浓度降低率达98%以上,并满足《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3-2007)中的限值要求。

The work investigated the chromium contaminated soil from a chemical plant in Changzhou after its demolition, with the method of reduction and stabilization remediation for hexavalent chromium contaminated soil. Single factor experiments were conducted to determine the best reductant and optimized conditions, and optimize the stable curing condition for reducing agent cost. The results show that the acidification of ferrous sulfate as the reducing agent, lime as curing agent, used in combination, can effectively reduce the concentration of hexavalent chromium in soil, the removal rate of hexavalent chromium in soil was higher than 98 %; hexavalent chromium and the total concentration of leaching toxicity reducing rate above 98 %, and the leaching concentrations were much lower than the limits listed in the National Standard GB 5085.3-2007