Anh Pham is an Assistant Professor in Civil and Environmental Engineering at Carleton University (Ottawa, Canada). He obtained a BS in Chemical Engineering (Hanoi University of Technology), and a MS and PhD in Environmental Engineering (University of California Berkeley). His research is focused on ISCO remediation technologies, and water treatment technologies for the oil sands industry.
PLATFORM PRESESNTER - Oxidative and Reductive Treatments
Contaminant Oxidation by Heat-Activated Persulfate: Effect of Temperature on Transformation Pathway and Product Distribution
Heat activates persulfate into sulfate radical, a powerful oxidant capable of transforming a wide range of contaminants. Previous studies have shown that an increase in temperature accelerates the rates of sulfate radical production and contaminant degradation. However, few studies have considered the effect of temperature on the pathway through which contaminants are transformed. This presentation will discuss the effect of temperature (T = 22 – 70 ºC) on not only the kinetics of S2O82- activation but also on the contaminant transformation pathway and product distribution. In our study, benzoic acid (a model compound) was transformed by SO4•- via decarboxylation and hydroxylation mechanisms, with the decarboxylation mechanism becoming increasingly important at elevated temperatures. Polymerized products tend to be formed at elevated temperatures. Some of the products react directly with unactivated persulfate, resulting in faster persulfate consumption. The ability of sulfate radicals to initiate decarboxylation reactions and, more broadly, fragmentation reactions, as well as the effect of temperature on these transformation pathways will be discussed in the context of the transformation of contaminants such as PAHs and PCBs by heat-activated persulfate.