利用CPS还原稳定化修复Cr(Ⅵ)污染土壤  

Stabilization of Cr(Ⅵ)-contaminated soil with calcium polysulfide

作　　者：王婉玉[1] 刘元元[1] 黄思敏[1] 李余杰 周利强[2] 程榉 

机构地区：[1]重庆大学三峡库区生态环境教育部重点实验室,重庆400044 [2]重庆市固体废物管理中心,重庆401147

出　　处：《环境工程学报》2017年第6期3853-3860,共8页Chinese Journal of Environmental Engineering

基　　金：重庆市基础与前沿研究计划项目(CSTC2 014 JCYJA20016);中央高校基本科研业务费资助项目(106112014CDJZR210003)

摘　　要：通过研究多硫化钙(CPS)与水溶液中六价铬(Cr(Ⅵ))中的反应,得出CPS与Cr(Ⅵ)的化学计量关系及主要反应产物;以CPS为修复剂,开展还原稳定化法对Cr(Ⅵ)污染土壤的修复实验,并用Fe SO_4作对比,比较两者的稳定化效果。结果表明:CPS与水溶液中Cr(Ⅵ)反应的化学反应计量比为3∶2,对反应产物进行XRD表征,发现其主要成分为Cr(OH)3和单质S;CPS能够在短时间内大幅度降低砂土中总铬和Cr(Ⅵ)的浸出浓度以及土壤的Cr(Ⅵ)含量;经CPS处理之后的Cr(Ⅵ)污染土壤,pH值从原来的8.9下降至8.2,而经Fe2+处理的土壤明显酸化,其pH值降至7.5;土壤氧化还原电位(ORP)先显著下降,后期随着CPS的逐步消耗稍有上升;经CPS稳定化处理后,土壤可交换态铬和碳酸盐结合态铬均明显减少,铬的稳定性增强,环境风险显著减小。Experiments were conducted to investigate the reaction stoichiometry and main products of hexavalent chromium （Cr（Ⅵ）） reduction with calcium polysulfide （CPS） in the aqueous phase.Batch experiments were also performed to compare the stabilization effectiveness of Cr（Ⅵ） in contaminated soil with CPS with that of ferrous sulfate （FeSO4）.A CPS：Cr（Ⅵ） molar ratio of 1.5 was required for the complete reduction of Cr（Ⅵ） in aqueous solutions.X-ray diffraction （XRD） analysis revealed that the main reaction products were Cr（OH）3 and elemental sulfur.CPS rapidly and effectively decreased the Cr（Ⅵ） content of the studied sandy soil and reduced the leaching of Cr and Cr（Ⅵ） from soil.The pH of CPS-treated soil decreased slightly from 8.9 to 8.2.Further, the soil apparently acidified after FeSO4 treatment, as the pH dropped to 7.5.After the addition of CPS, the redox potential （ORP） of treated soil sharply decreased and then gradually rose with the consumption of CPS.The exchangeable and carbonate fractions of chromium in CPS-treated soil apparently decreased, achieved greater stability of Cr, and reduced potential environmental risks.

关 键 词：Cr(Ⅵ) CPS 污染土壤 还原稳定化 

分 类 号：X53[环境科学与工程—环境工程]