Evaluation of Electrocatalytic Ozonation Process for Hydroxyl Radical Production

This paper seeks to evaluate the effect of reaction parameters on iron electrolysis-catalyzed ozonation (ECO) performance as a promising approach for micropollutant removal. ECO is proposed to be an environmentally and economically suitable technology for the removal of biologically recalcitrant organics in wastewater. In this process, iron ions generated via electrolysis of low-carbon steel react with dissolved ozone to produce hydroxyl radicals. The removal of tert-Butyl alcohol (TBA) was selected as a performance indicator based on its significant resistance to direct ozonation compared to hydroxyl radicals, such that TBA removal denotes catalytic breakdown of ozone. TBA removal was measured with an HS-SPME-GC-MS method for precise quantification. ECO performance ranged from 7 to 77% TBA removal (from 0.73 mM initial concentration), varying depending on the tested levels of initial pH of 5, 7, and 9, applied current between 0.065 and 0.470 A, and ozone supply rate between 3.9 and 6.4 g/h. Performance was generally increased by pH, applied current, and ozone generation, converging at high applied current rates. The most efficient use of ozone was observed at pH 9 and 0.323 A, removing 32.2% of TBA per gram of ozone supplied.