Department of Chemistry, ‡Department of Soil and Crop Sciences and §Department of Civil and Environmental Engineering, Colorado State University , Fort Collins, Colorado 80523, United States.
Environ Sci Technol. 2016 Aug 16;50(16):8817-26. doi: 10.1021/acs.est.6b02183. Epub 2016 Jul 29.
1,4-dioxane is an emerging groundwater contaminant with significant regulatory implications. Because it is resistant to traditional groundwater treatments, remediation of 1,4-dioxane is often limited to costly ex situ UV-based advanced oxidation. By varying applied voltage, electrical conductivity, seepage velocity, and influent contaminant concentration in flow-through reactors, we show that electrochemical oxidation is a viable technology for in situ and ex situ treatment of 1,4-dioxane under a wide range of environmental conditions. Using novel titanium dioxide (TiO2) pellets, we demonstrate for the first time that this prominent catalyst can be activated in the dark even when electrically insulated from the electrodes. TiO2-catalyzed reactors achieved efficiencies of greater than 97% degradation of 1,4-dioxane, up to 4.6 times higher than noncatalyzed electrolytic reactors. However, the greatest catalytic enhancement (70% degradation versus no degradation without catalysis) was observed in low-ionic-strength water, where conventional electrochemical approaches notoriously fail. The TiO2 pellet's dark-catalytic oxidation activity was confirmed on the pharmaceutical lamotrigine and the industrial solvent chlorobenzene, signifying that electrocatalytic treatment has tremendous potential as a transformative remediation technology for persistent organic pollutants in groundwater and other aqueous environments.
1,4-二恶烷是一种新兴的地下水污染物，具有重要的监管意义。由于它能抵抗传统的地下水处理方法，因此 1,4-二恶烷的修复通常仅限于昂贵的原位紫外线高级氧化技术。通过在流动反应器中改变施加电压、电导率、渗流速度和进水污染物浓度，我们表明电化学氧化是一种可行的原位和异位处理技术，适用于广泛的环境条件下的 1,4-二恶烷。使用新型二氧化钛 (TiO2) 颗粒，我们首次证明即使与电极电隔离，这种突出的催化剂也可以在黑暗中被激活。TiO2 催化反应器对 1,4-二恶烷的降解效率超过 97%，比非催化电解反应器高 4.6 倍。然而，在离子强度低的水中观察到最大的催化增强（降解 70%，而没有催化则没有降解），在这种水中，传统的电化学方法通常会失效。TiO2 颗粒的暗催化氧化活性在药物拉莫三嗪和工业溶剂氯苯上得到了证实，这表明电催化处理作为一种变革性的修复技术，在地下水和其他水相环境中对持久性有机污染物具有巨大的潜力。
