Ozonation and ozone-based advanced oxidation processes (such as O3/H2O2 and O3/catalytic by metal oxides) have been widely used, and the hydroxyl radical (OH�) generated via the complex chain reactions (including initiation, propagation, and termination reactions) is able to eliminate the highly resistant organic micro-pollutants. Considering the OH� scavenging rate of the water matrix, the effectiveness of these micro-pollutants oxidation is depended on the yield of OH� formed in these processes. Thus, a comprehensive evaluation on the OH� yield (F) in these processes is necessary. Firstly, the tert-Butanol (tBuOH) assay was utilized to determine the F values in the catalytic ozonation by metal oxides. The ? values was determined to be in the range of 10%~50%, and the large difference for varies metal oxides implied different catalytic mechanisms, such as OH� and non-OH� mechanisms. Secondly, two methods (the tBuOH assay and the competition method) were compared utilized to determine the F values in the case of real waters. Simulated analysis indicated that the propagation reactions contributed a lot on the OH� production and significantly affected the role of catalytic processes (such as metal oxides) on the OH� yield. These results were proposed to better guide the practical application of the ozone-based advanced oxidation processes.

Hydroxyl radical formation and eficiency evaluation in ozonation and ozone-based advanced oxidation processes

248th National Meeting (2014)

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