• 关键词：铬污染土壤  硫化物  多硫化钙  稳定化

• 基金项目：国家环境保护公益性行业科研专项项目（No.201509035）

• 卢鑫
• 1. 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237

• 罗启仕
• 永清环保股份有限公司上海分公司, 上海 200051

• 刘馥雯
• 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237

• 王漫莉
• 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237

• 林匡飞
• 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237

• 崔长征
• 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237

• 摘要：以某电镀厂旧址内的铬（Cr）污染土壤为研究对象，分别添加多硫化钙（CPS）、硫化钠（Na₂S）以及焦亚硫酸钠（Na₂S₂O₅）3种硫化物稳定剂，探究3种稳定剂不同投加摩尔比对土壤中Cr的价态变化、浸出毒性和形态分布的影响.结果表明：CPS对Cr（Ⅵ）还原效果最佳，当CPS投加摩尔比为3时，土壤中Cr（Ⅵ）含量从1587.5 mg·kg^-1减少至12.43 mg·kg^-1，还原效率高达99.2%，然而相同条件下Na₂S和Na₂S₂O₅对Cr（Ⅵ）的还原效率仅分别为55.6%和74.5%.CPS对Cr（Ⅵ）和总Cr稳定效率最高，当CPS投加摩尔比为3时，浸出Cr（Ⅵ）和总Cr浓度分别为0.02 mg·L^-1和0.32 mg·L^-1，Cr（Ⅵ）和总Cr稳定效率分别为99.8%和99.1%，此时Cr（Ⅵ）浓度满足GB/T 14848-93《地下水水质标准》规定的限值.相同投加摩尔比下Na₂S和Na₂S₂O₅对Cr（Ⅵ）稳定效率分别仅为63.0%和98.9%，对总Cr稳定效率分别为66.5%和77.2%；浸出Cr（Ⅵ）和总Cr浓度随着CPS和Na₂S投加摩尔比的增加而降低，然而随着Na₂S₂O₅投加摩尔比的增加，浸出Cr（Ⅵ）浓度持续下降，但总Cr浓度不断升高.CPS和Na₂S稳定化后土壤中Cr的有机物结合态变化不大（p>0.05）、铁锰氧化物结合态显著增加（p<0.05）.硫化物稳定剂稳定化后土壤中Cr的可交换态含量的变化是影响浸出总Cr浓度变化的主要原因.基于3种硫化物稳定剂对土壤中Cr（Ⅵ）还原效率、Cr（Ⅵ）和总Cr稳定效率和Cr的可交换态含量的影响，CPS投加摩尔比为3时，对该电镀厂铬污染土壤的稳定化效果最佳.

• Abstract：This study aims to investigate the effects of valance change, leaching toxicity and fraction distribution for stabilization of Cr (Ⅵ) using sulfide-based stabilizers (calcium polysulfide (CPS), sodium sulfide (Na₂S) and sodium metabisulfite (Na₂S₂O₅)). The results showed the maximum decrease in Cr (Ⅵ) contents from 1587.5 mg·kg^-1 to 12.43 mg·kg^-1 was achieved with an efficiency of 99.2% at CPS molar ratio of 3. In comparison, the reduction efficiencies by Na₂S and Na₂S₂O₅ under the same condition were 55.6% and 74.5%, respectively. CPS shows the highest stabilization effect to Cr (Ⅵ) and total Cr. At CPS molar ratio of 3, the stabilization efficiency of 99.8% and 99.1% was reached for 0.02 mg·L^-1 of Cr (Ⅵ) and 0.32 mg·L^-1 of total Cr concentration, respectively. The Cr (Ⅵ) concentration is well below the standard limit (0.05 mg·L^-1) specified in GB/T 14848-93. With the same molar ratio of Na₂S and Na₂S₂O₅, stabilization efficiency of Cr (Ⅵ) were 63.0% and 98.9% and that of total Cr were 66.5% and 77.2%, respectively. The concentrations of Cr (Ⅵ) and total Cr decreased with increased dosages of CPS and Na₂S, while Cr (Ⅵ) concentration decreased but total Cr continued to increase with increased dosage of Na₂S₂O₅. The fraction change of organic matter was little (p > 0.05) but iron and manganese oxides increased significantly (p < 0.05) in soil stabilized by CPS or Na₂S. The change of exchangeable content of Cr in soil stabilized by sulfide-based stabilizers was the main reason for the change of total Cr concentration. Based on Cr (Ⅵ) reduction efficiency by three types of sulfide-based stabilizers, stabilization efficiency of Cr (Ⅵ) and total Cr and the exchangeable content of Cr, the best stabilizing effect was observed at CPS molar ratio 3 for the soil contaminated by chromium in electroplating factory.

• Key words：chromium contaminated soils  sulfides  calcium polysulfide  stabilization

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