曝气强化非离子表面活性剂洗涤法修复柴油污染土壤

摘要

The diesel-contaminated soil was remediated by ex-situ aeration enhanced washing method with nonionic surfactant. The factors affecting the washing effect were investigated,and the washing mechanism was studied by determination of surface tension and contact angle. The experimental results show that:The washing effect of diesel oil from diesel-contaminated soil can be enhanced by aeration and the removal rate of diesel oil is increased by 10%-20%;The order of washing effect by 3 kinds of nonionic surfactants is Brij-35>TX-100>Tw-80;Under the optimum conditions of Brij-35 concentration one time of CMC,aeration rate 7.5 L/min,washing time 60 mine and washing solution pH 11.0,the removal rate of diesel oil is 77.4%,the oil content of the diesel-contaminated soil is decreased from 7.0%to 1.6%,the contact angle is decreased from 24.12° to 6.65°,and the hydrophily of the soil can be recovered after washing;The surface tension of the washing solution is decreased with the increase of surfactant concentration,but not affected by washing solution pH.%采用异位修复法，利用非离子表面活性剂洗涤柴油污染土壤，并在洗涤过程中曝气强化。考察了洗涤效果的影响因素，并通过表面张力和接触角的测定探讨了洗涤机理。实验结果表明：曝气对污染土壤中柴油的洗脱有强化作用，可提高洗脱率10%~20%；3种非离子表面活性剂的洗脱效果优劣次序为聚氧乙烯月桂醚（Brij-35）>曲拉通X-100（TX-100）>吐温-80（Tw-80）；在表面活性剂浓度为1倍临界胶束浓度、曝气量为7.5 L/min、洗涤时间为60 min、洗涤液pH为11.0的优化条件下，Brij-35对柴油的洗脱率达77.4%，污染土样的含油率从7.0%降至1.6%，接触角从24.12°降至6.65°，可基本恢复土壤的亲水性；洗涤液的表面张力随表面活性剂浓度的增加而降低，但不受洗涤液pH的影响。