由于其不利的健康和环境影响,诸如氯化溶剂之类的有毒有机化合物对地下水的污染是全球关注的问题。缓释高锰酸盐凝胶(SRP-G)是高锰酸钾(KMnO4)和胶体二氧化硅溶液的混合物。SRP-G设计为通过井注入后径向扩散,原位凝胶化以形成含有高锰酸盐(MnO4-)的凝胶屏障,并缓慢释放MnO4-以处理地下水中氯化溶剂的羽流。本研究旨在表征温度对饱和多孔介质中SRP-G动力学的影响。在凝胶化批量测试中,室温(24oC)SRP-G与30g/L-KMnO4的粘度为21cP在70分钟,176分钟时134cP,并在946cP达到峰值,在229分钟凝固。含30g/L-KMnO4的低温(4oC)SRP-G的粘度在273分钟时为71cP,402cP在392分钟,并在818cP达到峰值,在485分钟凝固。类似的模式,例如,低温SRP-G凝胶滞后时间增加,对于40g/L的SRP-Gs观察到,50g/L,和60g/L的KMnO4。在使用充满饱和砂的玻璃柱的流通测试中,注射速率,扩散率,释放持续时间为0.6毫升/分钟,46mm/min,KMnO4(aq)33小时,0.2mL/min,2mm/min,和38小时的环境温度SRP-G,0.4毫升/分钟,16mm/min,低温SRP-G为115小时,分别。这些结果表明,可注射性,注射速率,以及SRP-G的胶凝滞后时间和尺寸,释放速率,在低温下可以增加MnO4-凝胶屏障的释放持续时间。低温SRP-G方案可用于处理地下水中氯化溶剂或其他污染物的大的或稀的溶解羽流。
Due to its adverse health and environmental impacts, groundwater contamination by toxic organic compounds such as chlorinated solvents is a global concern. The slow-release permanganate gel (SRP-G) is a mixture of potassium permanganate (KMnO4) and colloidal silica solution. The SRP-G is designed to radially spread after injection via wells, gelate in situ to form gel barriers containing permanganate (MnO4-), and slowly release MnO4- to treat plumes of chlorinated solvents in groundwater. This study aimed to characterize the effects of temperature on the dynamics of SRP-G in saturated porous media. In gelation batch tests, the viscosity of ambient-temperature (24 °C) SRP-G with 30 g/L-KMnO4 was 21 cP at 70 min, 134 cP at 176 min, and peaked at 946 cP to solidification at 229 min. The viscosity of low-temperature (4 °C) SRP-G with 30 g/L-KMnO4 was 71 cP at 273 min, 402 cP at 392 min, and peaked at 818 cP to solidification at 485 min. A similar pattern, e.g., increased gelation lag time with low-temperature SRP-G, was observed for SRP-Gs with 40 g/L, 50 g/L, and 60 g/L KMnO4. In flow-through tests using a glass column filled with saturated sands, injection rates, spreading rates, and release durations were 0.6 mL/min, 46 mm/min, and 33 h for KMnO4(aq), 0.2 mL/min, 2 mm/min, and 38 h for ambient-temperature SRP-G, and 0.4 mL/min, 16 mm/min, and 115 h for low-temperature SRP-G, respectively. These results indicated that the injectability, injection rate, and gelation lag time of SRP-G and the size, release rate, and release duration of MnO4- gel barriers can be increased at low temperatures. The low-temperature SRP-G scheme can be useful for treating large or dilute dissolved plumes of chlorinated solvents or other pollutants in groundwater.