Abstract:

In this paper,first,CeO₂ -ZSM-5 zeolite catalysts were prepared by means of impregnation method and were applied to the catalytic wet peroxide oxidation of phenol in a fixed bed reactor.Then,the phase structure,specific surface area and pore structure of CeO₂ -ZSM-5 were characterized via XRD and N₂adsorption-desorption.Finally,the effects of temperature,bed height and feed flow rate on the conversion rates of phenol,H₂O₂ and total organic carbon (TOC),as well as on the cerium leaching concentration and the selectivity of CO₂ ,were investiga- ted.Characterization results show that CeO₂ -ZSM-5 catalysts are micro-pore materials; and that，after the loading of active components,the crystal form of CeO₂ -ZSM-5 almost keeps unchanged but the specific surface area decrea- ses.Moreover,from the activity evaluation results,it is found that (1) the conversion rates of phenol,H₂O₂ and TOC,as well as the selectivity of CO₂ all increase with the increase of temperature and with the decrease of feed flow rate; (2) with the increase of bed height,the conversion rates of phenol,H₂O₂ and TOC all increase,while the selectivity of CO₂ decreases; (3) the cerium leaching concentration is small under all conditions,which means that the catalysts possess good stability; and (4) no by-products are observed in the process of CWPO.

Key words: phenol, fixed bed reactor, catalytic wet peroxide oxidation, impregnation method, catalyst activity