Fundamental study on efficiency and safety of washing-reagent-injection as a remediation technique for soil and groundwater pollution

为了解氯化有机溶剂污染的土壤/地下水修复新技术--洗涤剂注入的有效性和安全性，研究了表面活性剂和高分子量有机物共存对三氯乙烯(TCE)水溶解度的影响、三氯乙烯在玻璃微珠填充柱中的重力驱动迁移行为以及零价铁粉对三氯乙烯的还原脱氯分解。几种表面活性剂显著提高了三氯乙烯的溶解度，但一些表面活性剂和高相对分子质量的有机物对三氯乙烯的溶解度没有影响。未稀释的三氯乙烯在洗涤剂饱和色谱柱中的迁移行为与所测试的化学品有很大的不同。一些表面活性剂引入了重力驱动的大范围CON…快速迁移在脱氯反应中，三氯乙烯的量减少，观察到顺式-1，2-二氯乙烯的形成。当溶液中不含添加剂时，TCE的分解对-TCE和零价铁的浓度是一级的。有添加剂时三氯乙烯的分解速率低于无添加剂时的速率：阳离子表面活性剂十六烷基三甲基溴化铵的速率常数降低了0.7倍，阴离子表面活性剂正十二烷基苯磺酸钠、正十二烷基硫酸钠和正十二烷基磺酸钠以及高相对分子质量有机化合物可溶性淀粉、β-环糊精和聚乙二醇6000的速率常数降低了0.5倍；对月桂酸钠和非离子表面活性剂Triton X-100、Tween20、Tween60、Brij35、Brij58的影响因子为0.2。对于这项技术的实际应用，建议对几个因素进行全面的评估

To learn efficiency and safety of washing-reagent-injection, a new soil/groundwater remediation technique for chlorinated organic solvent pollution, the effects of coexisting surfactants and high-molecular-weight organic compounds on the water solubility of trichloroethylene (TCE), the gravity-driven migration behavior of TCE in a glass-bead-packed column, and the reductive dechlorination decomposition of TCE with zerovalent iron powder were investigated.The effect of reagent type and concentration on TCE solubility and migration behavior in glass-bead-packed columns appeared severally each other. Several of the surfactants drastically increased the solubility of TCE, but some surfactants and the high-molecular-weight organic compounds had no effect on TCE solubility. The migration behaviors of undiluted TCE in the washing-reagent-saturated columns differed substantially for the tested chemicals. Some of the surfactants introduced rapid gravity-driven migration over a wide range of con … More centrations.During the dechlorination reaction, the amount of TCE decreased, and the formation of cis-1,2-dichloroethylene was observed. The decomposition of TCE was found to be first order with respect to the-TCE and zerovalent iron concentrations when the solution contained no additives. The rates of decomposition of TCE in the presence of the additives were lower than the rate in the absence of the additives: the rate constant was reduced by a factor of 0.7 for the cationic surfactant cetyltrimethylammonium bromide; by a factor of 0.5 for the anionic surfactants sodium n-dodecylbenzenesulfonate, sodium n-dodecylsulfate, and sodium n-dodecanesulfonate and for the high-molecular-weight organic compounds soluble starch, β-cyclodextrin, and polyethyleneglycol 6000;and by a factor of 0.2 for sodium laurate and the nonionic surfactants Triton X-100,Tween 20,Tween 60,Brij 35,and Brij 58.The results indicate that the washing-reagent-injection method contains several advantages and disadvantages. Importance of thoroughly assessment for several factors is suggested for the practical use of this technique Less