CONTROLLING BROMATE FORMATION BY CONVENTIONAL AND INNOVATIVE TITANIUM DIOXIDE PHOTOCATALYSIS

Abstract

Suspended titanium dioxide (TiO2) nanoparticles produce hydroxyl radicals (•OH) that synergistically aid in disinfection when irradiated with UV light. To exploit the benefits of TiO2 photocatalysis without having to remove them, TiO2 was deposited onto 3M Company’s nanostructured thin film (NSTF). •OH production by suspended and TiO2-NSTF was determined by para-chlorobenzoic acid (pCBA), a •OH probe compound. Both techniques of introducing TiO2 to the samples produced equivalent •OH without forming bromate, a regulated byproduct in drinking water at all UV and TiO2 levels. Formation of bromate by ozone in brackish water and seawater were used to compare the disinfection byproduct (DBP) formation between the disinfection methods. Additionally, monitoring bromate, typically performed by ion chromatography, is complicated by chloride and other anions present in brackish water or seawater. Thus, a spectrophotometric method to measure bromate in saline systems is introduced.