Reactivity of hydroxyl radical: mechanistic insight into the reactivity with dissolved organic matter

Advanced Oxidation Processes (AOPs) that produce highly reactive hydroxyl radicals (HO•) are attractive and promising water and wastewater treatment technologies because HO• can destroy a variety of organic compounds. However, background dissolved organic matter (DOM) significantly reduces the performance of AOPs by scavenging HO•. The conventional experimental approach to identifying ‘average’ reactivity limits our mechanistic understanding of the reaction of HO• with complex mixture of surrogate DOM. This is the first study to use quantum mechanical methods to understand the elementary reactions of HO• with a model monomer of DOM. “Temple Northeastern Birmingham model” (TNB). The theoretically calculated aqueous-phase free energies of activation indicate that the functional groups in neighboring positions significantly affect the reactivity of HO• with each active site of the TNB model monomer of DOM.