Oxygen vacancy of CeO2 improved efficiency of H2O2/O3 for the degradation of acetic acid in acidic solutions

In order to completely mineralization of contaminants, it is necessary to develop new methods which can effectively degrade final products of chemical oxidation. Acetic acid (HAc) has been considered one of the typical end products of chemical oxidation of pollutants and thus chosen as a representative target pollutant in the study. Nano-cerium oxide (CeO2), an environment-friendly rare-earth material, was prepared to catalytic ozonation of HAc in acidic solutions. Experimental results show that the prepared CeO2 could greatly enhance efficiency of H2O2/O3, and also have good stability and recyclability. The Raman spectra indicate that H2O2 interacts with oxygen vacancies of CeO2 to form peroxide-like species, which could effectively initiate the decomposition of ozone to produce hydroxyl radicals. A mechanism is proposed to explain the activity of peroxide-like species for the decomposition of ozone. The effects of different parameters such as initial pH value, catalyst dosage, and the concentration of H2O2 are also investigated. The results indicate that the CeO2/H2O2/O3 may provide a convenient and effective method for degrading refractory organic pollutants in acidic wastewaters.