Degradation of bisphenol S – a contaminant of emerging concern - by synergistic ozone and percarbonate based AOP

Degradation of bisphenol S was studied using ozone activated by sodium percarbonate and the effectiveness of optimized process was compared with the peroxone process. The influence of several factors including sodium percarbonate concentration, ozone dose, pH, and water matrix were investigated. A synergetic coefficient of 3.84 was achieved for the combination of sodium percarbonate and ozone, confirming the effectiveness of this hybrid process. Scavenging tests revealed, that carbonate radicals, hydroxyl radicals, superoxide radicals, and singlet oxygen contributed to the degradation of bisphenol S. At the same operating condition, degradation effectiveness values of 99% and 81% were obtained by ozone combined with sodium percarbonate and hydrogen peroxide, respectively, demonstrating the superiority of sodium percarbonate over hydrogen peroxide in combination with ozone for the degradation of bisphenol S. Low concentration of inorganic anions had a negligible effect on the degradation, while carbonate ions increased the first-order degradation rate constant by 56%.