Study on enhanced ozonation degradation of para-chlorobenzoic acid by peroxymonosulfate in aqueous solution

Enhanced ozonation degradation of para-chlorobenzoic acid (pCBA) with the addition of peroxymonosulfate (PMS) was investigated in aqueous solution. The results demonstrated that the addition of PMS could accelerate the decomposition of O3 by 50 times compared to that of O3 alone, and the effect was comparable to that of hydrogen peroxide. The degradation of a typical organic contaminant pCBA, was significantly enhanced by the addition of O3/PMS. The mechanism behind the synergistic effect was preliminarily explored by the addition of hydroxyl and sulfate radical (SO4-) scavengers. The degradation of pCBA by O3/PMS could not be completely inhibited by tert-butanol, whereas it was inhibited by the addition of methanol, indicating that the effect of O3/PMS was primarily due to the production of a greater amount of SO4-. The addition of O3/PMS had a selective effect on various contaminants. The enhanced degradation of pCBA by O3/PMS was also observed in actual water samples, and provided some impetus for practical applications of the developed system.