生物与化学表面活性剂协同洗脱土壤中PCBs的研究

通过序批实验和土柱淋洗实验研究了由生物表面活性剂鼠李糖脂(RL)与非离子化学表面活性剂十二烷基醇聚氧乙烯(6)醚(POE(6))混合得到的复配试剂洗脱污染土壤中多氯联苯(PCBs)的作用效果及其作用机理。结果表明,同一土样中,从批实验得到的PCBs洗脱率略高于土柱淋洗实验。RL与POE(6)两种单一试剂对人工污染土样中的PCBs洗脱率均大于60%,而对陈化土样中的洗脱率均不到20%,且土壤中的TOC含量越高,PCBs的洗脱率越低。在质量浓度为301 mg/L(10 CMC)及1 505 mg/L(50 CMC)的RL-POE(6)复配试剂中,RL与POE(6)对人工污染土壤中PCBs的洗脱具有一定的协同作用。当复配试剂的浓度为301 mg/L时,RL与POE(6)对陈化土样中PCBs的洗脱没有协同作用;但当RL-POE(6)的浓度增加到1 505 mg/L时,RL与POE(6)对陈化土样中PCBs的洗脱具有明显的协同作用。

Study on synergistic desorption of polychlorinated biphenyls(PCBs) by biosurfactant and chemical surfactant from contaminated soils

Batch experiments and column experiments were performed to study synergistic desorption of polychlorinated biphenyls(PCBs) from contaminated soils by biosurfactant rhamnolipid(RL) and chemical surfactant,polyoxyethylene 6 lauryl ether(POE(6)).The results showed that desorption percentage of PCBs from the same soil by batch experiment was slightly higher than that by soil column experiment.Desorption rate of PCBs from laboratory contaminated soil by RL or POE(6) was more than 60%,but that from field contaminated soil was less than 20%.The greater the TOC of soils,the lower the desorption rate of PCBs.At binary mixed-surfactants concentration of 301 mg/L(10 CMC) and 1 050 mg/L(50 CMC),PCBs from laboratory contaminated soil were obviously synergistically desorbed by RL and POE(6).At the concentration of 301 mg/L,PCBs from field contaminated soil were not able to be synergistically desorbed by RL and POE(6).When the concentration increased from 301 mg/L to 1 050 mg/L,PCBs from field contaminated soil were obviously synergistically desorbed by RL and POE(6).