Li Zhaohui
Department of Geosciences, University of Wisconsin--Parkside, 900 Wood Road, Box 2000, Kenosha, WI 53144-2000, USA.
Chemosphere. 2004 Jan;54(3):419-23. doi: 10.1016/S0045-6535(03)00752-5.
Oxidative dechlorination of chlorinated solvents by permanganate is an emerging technology for remediation of groundwater contaminated with dissolved chlorinated contaminants. In this study, the enhancement of trichloroethylene (TCE) degradation by permanganate in aqueous solution in the presence of surfactant was evaluated through a continuous stir batch reactor system with the presence of permanganate as the limiting reagent and free phase TCE. The TCE degradation was determined by continuous monitoring the amount of chloride produced, which was then reverted to the rate of permanganate consumption. It was found that the chloride production, an indication of TCE degradation, followed a pseudo-first-order reaction kinetics with respect to KMnO(4) in the presence of free phase TCE. When no surfactants were present, the observed pseudo-first-order rate constant (k(obs)) was 0.08-0.19 min(-1) and the half-life (t(1/2)) was 4-9 min for MnO(4)(-). When the surfactant concentration was less than its critical micelle concentration (CMC), the k(obs) values increased to 0.42-0.46 min(-1) and the t(1/2) reduced to 1.5-1.7 min for MnO(4)(-). As the surfactant concentration was greater than the CMC, the k(obs) values increased to 0.56-0.58 min(-1) and the t(1/2) reduced to 1.2-1.3 min. The preliminary results showed that combination of permanganate with a proper type of surfactant can speed up contaminant removal.
通过高锰酸盐对氯化溶剂进行氧化脱氯是一种用于修复被溶解的氯化污染物污染的地下水的新兴技术。在本研究中，通过连续搅拌间歇式反应器系统，在高锰酸盐作为限量试剂且存在游离相三氯乙烯（TCE）的情况下，评估了表面活性剂存在时高锰酸盐对水溶液中三氯乙烯（TCE）降解的增强作用。通过连续监测产生的氯化物量来确定TCE的降解情况，然后将其转化为高锰酸盐的消耗速率。结果发现，在存在游离相TCE的情况下，作为TCE降解指标的氯化物生成遵循关于KMnO₄的准一级反应动力学。当不存在表面活性剂时，观察到的准一级速率常数（k(obs)）为0.08 - 0.19 min⁻¹，MnO₄⁻的半衰期（t(1/2)）为4 - 9分钟。当表面活性剂浓度低于其临界胶束浓度（CMC）时，MnO₄⁻的k(obs)值增加到0.42 - 0.46 min⁻¹，t(1/2)降至1.5 - 1.7分钟。当表面活性剂浓度大于CMC时，k(obs)值增加到0.56 - 0.58 min⁻¹，t(1/2)降至1.2 - 1.3分钟。初步结果表明，高锰酸盐与适当类型的表面活性剂结合可以加快污染物的去除。
