The use of advanced oxidation process (AOPs) as a final wastewater remediation step is increasingly being considered because of the ability of AOPs to quantitatively remove all residual levels of contaminants. Quantitative removal of chemicals such as pharmaceuticals and carcinogens occurs through the generation and reactions of highly oxidizing radicals such as the hydroxyl radical (●OH). The ●OH radicals are typically generated through UV photolysis of hydrogen peroxide, and then they non-selectively react with, and degrade, all organic contaminant species in the wastewater. However, the efficiency of ●OH radical reactions within an AOP is affected by the presence of any contaminant chemicals, including wastewater matrix components, and intentionally added chloramines (NHxCly). While studies on chloramine based reactions have been performed, a potential wastewater contaminant that has received considerably less attention is bromide. The oxidizing reactions of hydroxyl or chlorine radical species with bromide ions can result in the production of bromine atoms (Br●). Alternative ways of bromine atom formation also include the radical reactions of bromamines (NHxBry), where the radicals are also produced under advanced oxidation conditions analogous to chlorine radical production from chloramines. Consequently, these Br● atoms formed by UV photolysis of bromamines could also potentially react with contaminant chemicals, assisting in remediation, or detrimentally react to produce brominated disinfection byproducts (DBPs). This study has investigated the reactivity of these bromine atoms with various wastewater chemical contaminants, notably nitrosamines and antibiotics. Preliminary kinetic data obtained for the reactivity of Br● with these contaminants suggests that kinetics of bromine atom reactions ranges of many orders of magnitude. It was found the average reactivity of bromine atom reactions is less than hydroxyl radical reactions, it may still be sufficient to assist in the remediation of wastewater chemical contaminants.

Bromine atom reactions under advanced oxidation process conditions

253rd National Meeting (2017)

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