Debromination of 2,4,6-Tribromophenol and bromate ion minimization in Water by catalytic ozonation

Abstract Catalytic ozonation of 2,4,6-Tribromophenol (2,4,6-TBP) in aqueous media conducted in the presence of 10%, 20% and 30% Co loaded on Fe by co-precipitation (Co-ppt) and a simple physical mixing method (Mixed), is compared to ozonation alone. In ozonation alone, only 40% of 2,4,6-TBP was converted, while 11% of TOC was removed from water. The surface characteristics of the catalysts material, determined by BET, NH 3 -TPD, SEM and point zero charge (pZ c ) measurements, revealed that the Fe-Co (Co-ppt) catalyst exhibited superior quality compared to Fe-Co (Mixed) catalyst material, hence contributing to higher catalytic activity for debromination of 2,4,6-TBP, TOC removal and organic by-product (Org-BP) minimization, however, it was unable to effectively limit bromate formation during ozonation. NH 3 -TPD and pZ c measurements showed that Fe-Co (Co-ppt) catalyst contained more acidic sites than Fe-Co (Mixed) catalyst, hence contributing to higher ozone decomposition to hydroxyl radicals. Fe-Co (Mixed) catalyst was more effective in inhibiting bromate formation. With 9:1 Fe-Co (Co-ppt) catalyst 39% of toxic bromate was formed during ozonation, while in the presence of 9:1 Fe:Co (Mixed) catalyst, a significant drop in bromate yield to 5% was achieved. A reaction pathway showing partial inhibition of bromate ion during catalytic ozonation in water is proposed.