表面活性剂和硫酸盐还原菌去除污染土壤中的Cr6+

用表面活性剂和硫酸盐还原菌(SRB)淋洗Cr污染土壤，采用欧洲共同体参考物机构连续提取法分析淋洗前后土壤中铬化学形态和相对含量的变化. 结果表明，阴离子表面活性剂十二烷基苯磺酸钠和非离子表面活性剂Tween-80浓度分别为5.0, 0.01 g/L时，对土壤中Cr的淋洗效果最好，当土壤中Cr含量为200 mg/kg时，淋洗率分别为14.70%和24.74%，500 mg/kg时，淋洗率为35.99%和41.42%；反应体系中菌液量为10 mL时，淋洗18 h上清液中Cr6+转化率最大，分别为98.07%和94.73%；用表面活性剂和SRB共同处理Cr污染土壤，上清液中Cr6+可全部转化为Cr3+，未被淋洗出的Cr从较易被植物利用的可交换态转化为稳定态，主要以Cr2(CO3)3和Cr(OH)3存在于土壤中，达到了土壤环境质量标准.

Removal of Cr6+ from Contaminated Soil by Surfactants and Sulfate-reducing Bacteria

The chemical status of Cr was analyzed by the European Community Bureau of Reference method. Cr contaminated soil was leached by surfactants and sulfate-reducing bacteria (SRB). The experimental results showed that sodium dodecyl benzene sulfonate and Tween-80 at the concentrations of 5.0 and 0.01 g/L could enhance the leaching rate. When the content of Cr in the soil was 200 mg/kg, the leaching rate of Cr6+ was 14.70% and 24.74%, when the content of Cr in the soil was 500 mg/kg, the leaching rate of Cr6+ was 35.99% and 41.42% respectively. When the microbial quantity in the reaction system was 10 mL, the leaching rate of Cr6+ at different contents of Cr (200, 500 mg/kg) reached 98.07% and 94.73% in 18 h respectively. By co-processing of surfactants and SRB, all leached Cr6+ was converted to Cr3+, the residual Cr6+ in the soil converted from availabilities into stable state, mainly in Cr2(CO3)3 and Cr(OH)3. After leaching with surfactant and SRB, the concentration of Cr6+ in the soil was up to the environment quality standards for soils.