生物柴油基微乳液的制备及其对钢铁厂多环芳烃污染土壤的修复性能

针对场地土壤中高浓度多环芳烃较难去除的问题，利用微乳液具有界面张力低、增溶能力强和体系稳定的特点，制备了污染土壤淋洗修复剂。采用表面活性剂、助表面活性剂、生物柴油为主要组分制备微乳液，优化微乳液最佳组分配比及制备条件，并比较表面活性剂、复配表面活性剂、生物柴油和微乳液等不同类型淋洗剂对钢铁厂污染土壤中多环芳烃的去除效果。结果表明，最佳微乳液组分及pH条件为：7.7% Tween-80、7.7% TX-100、15.4%正丁醇、20.5%生物柴油、pH=7。在不同类型的淋洗剂中，微乳液淋洗剂对多环芳烃的去除率最高(89.7%)，显著高于其他类型淋洗剂的效果。多环芳烃的去除率与淋洗剂和土壤的液固比、洗脱振荡时间等有关，确定的微乳液最佳修复条件为：液固比为4∶1、洗脱振荡时间为8 h。按混合表面活性剂与生物柴油比为6∶4制备的微乳液洗脱效果最佳。本研究结果可为高效去除污染土壤中多环芳烃打下基础。

Preparation of biodiesel-based microemulsion and its performance on the remediation of a steelworks soil contaminated with polycyclic aromatic hydrocarbons

Aiming at the difficulties in the removal of polycyclic aromatic hydrocarbons (PAHs) with high concentrations from contaminated soil, the washing agent for remediation of contaminated soil was prepared based on the characteristics of low interfacial tension, high solubility ability and stable system for microemulsion. Surfactants Tween-80 and TX-100, cosurfactant n-butanol, and biodiesel were taken as main components to prepare microemulsions. Component ratios and preparation conditions of the microemulsions were optimized, and the removal efficiencies of PAHs from a contaminated steelworks soil were compared among different kinds of washing agents: surfactants and their mixtures, biodiesel and the microemulsion. The results showed that the optimum microemulsion components were 7.7% Tween-80, 7.7% TX-100, 15.4% n-butanol and 20.5% biodiesel, and the optimum microemulsion preparation pH was7. Among different types of washing agents, the removal rate of PAHs by the microemulsion washing agent was the highest (89.7%), which was significantly higher than those by other types of washing agents. The removal rate of PAHs was related to the liquid-solid ratio of the washing agent and soil, and shaking time; the optimal conditions for the remediation with the microemulsion was liquid-solid ratio of 4∶1 and shaking time of 8 h. The microemulsion prepared with surfactant mixture-biodiesel ratio of 6∶4 showed the best soil washing effect and PAH removal. The microemulsion washing agent prepared in this study provides a new method for the efficient removal of PAHs in contaminated soil.