Catalytic wet air oxidation of phenol over CeO_2-TiO_2 catalyst in the batch reactor and the packed-bed reactor

摘要

CeO_2-TiO_2 catalysts are prepared by coprecipitation method, and the activity and stability in the catalytic wet air oxidation (CWAO) of phenol are investigated in a batch reactor and packed-bed reactor. CeO_2-TiO_2 mixed oxides show the higher activity than pure CeO_2 and TiO_2, and CeO_2-TiO_2 1/1 catalyst displays the highest activity in the CWAO of phenol. In a batch reactor, COD and TOC removals are about 100% and 77% after 120 min in the CWAO of phenol over CeO_2-TiO_2 1/1 catalyst at reaction temperature of 150 ℃, the total pressure of 3 MPa, phenol concentration of 1000 mg/L, and catalyst dosage of 4 g/L. In a packed-bed reactor using CeO_2-TiO_2 1/1 particle catalyst, over 91% COD and 80% TOC removals are obtained at the reaction temperature of 140 ℃, the air total pressure of 3.5 MPa, the phenol concentration of 1000 mg/L for 100h continue reaction. Leaching of metal ions of CeO_2-TiO_2 1/1 particle catalyst is very low during the continuous reaction. CeO_2-TiO_2 1/1 catalyst exhibits the excellent activity and stability in the CWAO of phenol.