冲洗液浸润性对去除砂质土残留油的影响

Influence of Flushing-Liquid's Wettability on Its Removal Efficency of Residual Oil from Sandy Soil

为获得含表面活性物质冲洗液的浸润性对其去除砂质土中残留油性能的影响关系,用直接量角法和铺展面积法共同对助溶剂、非离子表面活性剂、蒸馏水、柴油与石英玻璃接触角进行了测定,并用乙醇溶液、异丙醇溶液、Tween80和Brij35、蒸馏水等对含油石英砂柱进行冲洗试验.试验表明:随助溶剂浓度增大,其与石英的接触角减小,当乙醇体积分数超过70%、异丙醇体积分数超过40%,其与石英玻璃的接触角小于柴油与之的接触角,而非离子表面活性剂对石英的接触角大于该角度,表明醇类助溶剂比非离子表面活性剂对石英的浸润能力更强;当冲洗液与石英砂的接触角大于柴油与石英砂的接触角时浮油的产率基本不变,而小于该角度后浮油产量迅速增加;单孔隙体积的高浓度助溶剂溶液(体积分数为90%的乙醇)可去除87%残留油,预示助溶剂在修复油污染砂土的力方面有较好的应用潜力.

The contact angles of cosolvent, nonionic surfactant, distilled water and diesel to quartz glass were tested by direct angle measuring and spreading area reverse calculating, and diesel containing sand columns were flushed by Ethanol（EtOH） solution, isopropanol（IPA） solution, Tween80, Brij35 and distilled water to investigate the influence of wettability of flushing liquid that contains surface active chemicals on its removal efficiency of residual oil from sandy soil. The results show thats with the increase of cosolvent concentration, the con- tact angle to quartz glass decreases to contact angle of diesel to quartz when the concentration of EtOH is greater than 70%, and that of IPA greater than 40%, while angles of two nonionic surfactants to quartz glass are greater than that of diesel, which indicates cosolvent is more powerful than nonionic surfactant in increasing its wettability to solid; the product of free oil will not vary obviously with different flushing solution as long as contact angle of flushing solution to quartz is greater than that of diesel, while free oil product will rapidly increase when the contact angle of flushing solution to quartz is smaller than that of diesel; single pore volume of 90% of EtOH solution can remove 87% of residual oil from diesel-containing sandy column, which indicates cosolvent flushing has great application potential to sandy soil contaminated by LNAPL.