不同还原药剂修复Cr(Ⅵ)污染土壤的稳定性评估  

Stability evaluation of Cr(Ⅵ)-contaminated soils restoration with different reducing agents

作　　者：史开宇 王兴润[1] 范琴 沈重阳[2] 颜湘华[1] 李妍林 SHI Kaiyu;WANG Xingrun;FAN Qin;SHEN Chongyang;YAN Xianghua;LI Yanlin(State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;College of Resources and Environmental Sciences,China Agricultural University,Beijing 100193,China;Sichuan Academy of Environmental Sciences,Chengdu 610041,China)

机构地区：[1]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012 [2]中国农业大学资源与环境学院,北京100193 [3]四川省环境保护科学研究院,成都610041

出　　处：《环境工程学报》2020年第2期473-479,共7页Chinese Journal of Environmental Engineering

基　　金：国家重点研发计划项目(2018YFC1802200)。

摘　　要：针对目前铬污染场地修复后的长期稳定性问题,选用轻、重污染土壤和表层渣土混合物为研究对象,在分析其理化特性的基础上,对经CaS4、FeSO4·7H2O和葡萄糖还原后土壤的长期稳定性进行评估,通过设置干燥和淹水2个条件,探究了水分对Cr(Ⅵ)污染土壤长期稳定性的影响。结果表明:针对3种不同类型铬污染土壤,投加CaS4对土壤中Cr(Ⅵ)的还原效果较FeSO4·7H2O和葡萄糖好;在360 d的采样周期内,干燥条件下的3种土壤经CaS4处理后Cr(Ⅵ)浓度均保持稳定,经FeSO4·7H2O和葡萄糖药剂还原后,渣土混合物中Cr(Ⅵ)波动幅度较大,其余2种土壤呈稳定状态;淹水密闭条件下的3种土壤中Cr(Ⅵ)浓度均有下降趋势,特别是渣土混合物在投加FeSO4·7H2O和葡萄糖药剂处理后,下降趋势更为明显;在长期稳定性方面,在360 d的实验周期内,与淹水密闭条件相比,经还原修复后的Cr(Ⅵ)污染土壤在干燥条件下的稳定性更强;Cr(Ⅵ)污染土壤经还原后,有效的过量还原剂能在一定程度上抑制土壤中Cr(Ⅵ)浓度变化,且在淹水密闭条件下,土壤中Cr(Ⅵ)浓度呈下降趋势。Light and heavy Cr(Ⅵ)-contaminated soils and the mixture of Cr(Ⅵ) slag and soil were selected to study the long-term stability after Cr(Ⅵ)-contaminated soil remediation. Based on the physical and chemical properties of these soils, the long-term stability of the reduced soils by respective CaS4, FeSO4·7H2O or glucose were assessed. Under dry and flooding conditions, the effect of moisture on the long-term stability of the Cr(Ⅵ)-contaminated soil treated by reducing agents were investigated. The results showed that CaS4 had better reduction effect on the three kinds of contaminated soils than FeSO4·7H2O and glucose. During the 360 d sampling period, the Cr(Ⅵ) concentrations in these CaS4 reduced soils remained stable under dry condition. The Cr(Ⅵ) concentrations in the light and heavy polluted soils after the FeSO4·7H2O or glucose treatment remained stable, while the Cr(Ⅵ) concentration in the FeSO4·7H2O or glucose treated mixture of Cr(Ⅵ) slag and soil fluctuated greatly. Under flooding and sealing condition, the Cr(Ⅵ) concentrations in the three kinds of soil after reduction showed a decreasing trend. Especially, the Cr(Ⅵ) concentration in FeSO4·7H2O or glucose treated mixture of Cr(Ⅵ) slag and soil decreased significantly. During the 360 d sampling period, the Cr(Ⅵ)-contaminated soils after reduction remediation showed stronger long-term stability under dry condition than that under flooding condition. After Cr(Ⅵ)-contaminated soil remediation, excessive reducing agent could inhibit the change of Cr(Ⅵ) concentration in soil to certain extent, and the Cr(Ⅵ) concentration showed a decreasing trend under flooding condition.

关 键 词：长期稳定性评估 铬污染土壤 土壤修复 

分 类 号：X53[环境科学与工程—环境工程]