Catalytic wet air oxidation of phenol by various CeO2 catalysts.

Investigations of various CeO2 catalysts using XRD, 02-TPD, H2-TPR and catalytic wet air oxidation of phenol showed that CeO2 calcined under higher thermal impact (designated as type A) displayed excellent catalytic ability for the redox reaction of organics. Results of the investigations mentioned above showed that type A CeO2 has a less stable structure, more structure oxygen exchangeable and more oxidizing ability for the consumption of H2 and conversion of phenol. At phenol concentrations between 400 and 2,500 mg/L, oxygen pressure in the range of 0.5-1.0 MPa, and temperatures above 160 degrees C phenol conversion stood at > or = 90% after 4 h. Total organic carbon removal increased with the reaction temperature. Under the reaction conditions, CO2 selectivity was about 80% or more after 4 h reaction. The reduced catalytic ability of regenerated CeO2 was caused either by stabilization of CeO2 during the process of regeneration or by the deposition of some reaction residues.