【摘要】 为探索还原稳定化法修复六价铬污染土壤的工程可行性,以某化工厂铬渣堆存场内六价铬污染土壤为研究对象,开展还原稳定化法修复六价铬污染土壤的中试研究。结果表明,DARAMEND-M、硫酸亚铁(Fe SO4)和多硫化钙(CPS)3种药剂对土壤中Cr(Ⅵ)的还原率超过了99%,糖蜜对Cr(Ⅵ)的还原率达93.9%。经糖蜜和DARAMEND-M处理的下层土壤,水溶态铬+交换态铬由原来的21.77%分别下降至6.26%和2.95%;经Fe SO4和CPS处理的渣土混合物,水溶态铬+交换态铬由22.12%分别下降至4.58%和2.94%,铬的稳定性明显增强。采用糖蜜、DARAMEND-M和Fe SO4处理后可以降低土壤p H值,而CPS处理则提高土壤p H值;糖蜜和DARAMEND-M有助于提高土壤微生物量碳含量。总体而言,糖蜜和DARAMEND-M适合修复低Cr(Ⅵ)污染土壤,在还原稳定化效果和长效性方面,DARAMEND-M药剂优于糖蜜;Fe SO4和CPS在修复高Cr(Ⅵ)污染土壤方面具显著效果。更多还原

【Abstract】 Pilot scale treatability studies were conducted to evaluate the remediation of hexavalent chromium [Cr(Ⅵ) ]in soil at a former dump site of chromite ore processing residue(COPR).Our results showed that approximately 93.9% of Cr(Ⅵ) was reduced by molasses after a curing period of 45 days,whereas the average reduction percentage of Cr(Ⅵ) to Cr(Ⅲ) was more than 99% in soil treated with DARAMEND-M,ferrous sulfate(Fe SO4) and calcium polysulfide(CPS),respectively.The amount of easily soluble chromium(the water soluble + exchangeable fractions) decreased from 21.77% in the untreated subsoil to 6.26% and 2.95% in the soils subjected to molasses and DARAMEND-M,respectively,while the amount of easily soluble chromium(the water soluble + exchangeable fractions) decreased from 22.12% in the untreated surface soil to 4.58%and 2.94% in the soils subjected to Fe SO4 and CPS,respectively.The sequential extraction suggested that chromium was effectively stabilized.The p H of the treated soil increased with CPS addition,whereas treatment with molasses,DARAMEND-M and Fe SO4,respectively resulted in decrease in soil p H.Then,the addition of molasses or DARAMEND-M increased the microbial biomass C.It is concluded that,DARAMEND-M has more favorable properties for Cr(Ⅵ) treatment in soils with low Cr(Ⅵ) content compared to molasses;Fe SO4 and CPS are extremely effective in reduction and stabilization of Cr(Ⅵ) in soils with high Cr(Ⅵ) content.更多还原