The synergistic effect of O3 and H2O2 on the Butyl p-hydroxybenzoate photo-catalytic degradability by UVC/ZnO: efficiency, kinetic, pathway, mechanism

Abstract The present study was aimed to investigate on the synergistic effect of O3 and H2O2 on the Butyl p-hydroxybenzoate (BuP) photo-catalytic degradability by UVC/ZnO (UZ). To this purpose, degradability of BuP by UZ was studied in the presence and the absence of H2O2 and O3. The maximum performances of BuP degradation by UVC/ZnO (UZ), UVC/ZnO/H2O2 (UZH) and UVC/ZnO/O3 (UZO) after 15 min of reaction were achieved 38.12 %, 100 % and 96 %, respectively. Also, the observed rates of BuP degradation (robs (mg L-1 min)) by the, UZ, UZH and UZO were 0.21, 13.65 and 10.95 mg L-1 min, respectively. The values of energy consumption (EEO) for UZ, UZH and UZO in the removal of BuP were calculated 86.35 kW h m-3, 7.5 kW h m-3 and 12.8 kW h m-3, respectively. The maximum mineralization of BuP by UZH and UZO processes (under optimum operational conditions) were 37 % and 30 %, respectively.