Department of Civil and Environmental Engineering, Carleton University, Ottawa, ON K1S 5B6, Canada.
Department of Civil and Environmental Engineering, Carleton University, Ottawa, ON K1S 5B6, Canada.
Water Res. 2017 Sep 1;120:43-51. doi: 10.1016/j.watres.2017.04.066. Epub 2017 Apr 29.
Heat activates persulfate (SO) into sulfate radical (SO), a powerful oxidant capable of transforming a wide variety of contaminants. Previous studies have shown that an increase in temperature accelerates the rates of persulfate activation and contaminant transformation. However, few studies have considered the effect of temperature on contaminant transformation pathway. The objective of this study was to determine how temperature (T = 22-70 °C) influences the activation of persulfate, the transformation of benzoic acid (i.e., a model compound), and the distribution of benzoic acid oxidation products. The time-concentration profiles of the products suggest that benzoic acid was transformed via decarboxylation and hydroxylation mechanisms, with the former becoming increasingly important at elevated temperatures. The pathway through which the products were further oxidized was also influenced by the temperature of persulfate activation. Our findings suggest that the role of temperature in the persulfate-based treatment systems is not limited only to controlling the rates of sulfate and hydroxyl radical generation. The ability of sulfate radical to initiate decarboxylation reactions and, more broadly, fragmentation reactions, as well as the effect of temperature on these transformation pathways could be important to the transformation of a number of organic contaminants.
热将过硫酸盐（SO）激活为硫酸根自由基（SO），这是一种强大的氧化剂，能够转化多种污染物。先前的研究表明，温度的升高会加速过硫酸盐的活化和污染物的转化速率。然而，很少有研究考虑温度对污染物转化途径的影响。本研究的目的是确定温度（T=22-70°C）如何影响过硫酸盐的活化、苯甲酸（即模型化合物）的转化以及苯甲酸氧化产物的分布。产物的时-浓度曲线表明，苯甲酸通过脱羧和羟化机制转化，随着温度升高，前者变得越来越重要。产物进一步氧化的途径也受到过硫酸盐活化温度的影响。我们的研究结果表明，温度在过硫酸盐基处理系统中的作用不仅限于控制硫酸根和羟基自由基生成的速率。硫酸根自由基引发脱羧反应的能力，更广泛地说，引发碎片化反应的能力，以及温度对这些转化途径的影响，对于许多有机污染物的转化可能很重要。
