Catalytic ozonation of organic compounds in water over the catalyst of RuO2/ZrO2-CeO2

This research investigates the performances of RuO2/ZrO2-CeO2 in catalytic ozonation for water treatment. The results show that RuO2/ZrO2-CeO2 was active for the catalytic ozonation of oxalic acid and possessed higher stability than RuO2/Al2O3 and Ru/AC. In the catalytic ozonation of dimethyl phthalate (DMP), RuO2/ZrO2-CeO2 did not enhance the DMP degradation rate but significantly improved the total organic carbon (TOC) removal rate. The TOC removal in catalytic ozonation was 56% more than that in noncatalytic ozonation. However this does not mean the catalyst was very active because the contribution of catalysis to the overall TOC removal was only 30%. The adsorption of the intermediates on RuO2/ZrO2-CeO2 played an important role on the overall TOC removal while the adsorption of DMP on it was negligible. This adsorption difference was due to their different ozonation rates. In the catalytic ozonation of disinfection byproduct precursors with RuO2/ZrO2-CeO2, the reductions of the haloacetic acid and trihalomethane formation potentials (HAAFPs and THMFPs) for the natural water samples were 38%–57% and 50%–64%, respectively. The catalyst significantly promoted the reduction of HAAFPs but insignificantly improved the reduction of THMFPs as ozone reacts fast with the THMs precursors. These results illustrate the good promise of RuO2/ZrO2-CeO2 in catalytic ozonation for water treatment.