不同化学还原体系下铬污染土壤的处理效率

以某场地两种典型铬污染土壤（Soil A和Soil B）为研究对象，探讨了不同药剂对土壤Cr6+的还原效果以及洗脱效果。结果表明，Na2S较FeSO4对土壤中Cr6+有更好的还原效果，还原率和总还原效率均可大于99%；具体工艺参数为：Na2S添加倍数5倍且pH值5~7。FeSO4和Na2S对Cr6+均有很好的洗脱效果，可将两种土壤洗脱液中Cr6+还原完全（未检出）；具体工艺参数：FeSO4添加倍数5倍且pH值5~7或者Na2S添加倍数5倍且pH值5。综合考虑还原和洗脱效果，最优的工艺参数为Na2S添加倍数5倍且pH值5。通过经济性分析，处理1 t污染土壤Soil A和Soil B的药品费用分别为3.55元和59.52元。

Remediation efficiency of chromium contaminated soil under different redox systems

Two different types of chromium slag-contaminated soil (soil A and soil B treatments) were selected as test samples for the investigation of Cr6+ removal and the elution efficiencies of typical stabilization agents.The main findings are as follows:The hexavalent chromium reduction efficiency of Na2S was better than that of FeSO4.The Cr6+ removal rate and total reduction efficiency of Na2S exceeded 99% in both soil treatments.Meanwhile, the proper quantity of additional Na2S was five times the theoretical quantity, and the pH was 5~7.The elution efficiency was good for both Na2S and FeSO4.The Cr6+ of the eluent was almost completely reduced by both soil treatments (not detected).The proper quantity of additional FeSO4 was five times the theoretical quantity, and the pH was 5~7.Moreover, the proper quantity of Na2S was also five times the theoretical quantity, with a pH of 5.In terms of removal and elution efficiencies, the optimal parameter was an Na2S quantity five times that of the theoretical quantity, with a pH of 5~7.From an economic analysis, the costs of treatment for one ton of contaminated soils A and B were determined to be RMB 3.55 and 59.52 Yuan, respectively.