Overall rate of aqueous-phase catalytic oxidation of phenol: pH and catalyst loading influences

The catalytic oxidation of phenol in aqueous-phase has been investigated us ing a commercial catalyst CuO-2(CuO). Cr2O3-CrO4Ba-Al2O3 at 400 K and an ox ygen pressure of 8 atm, changing the pH and catalyst concentration. The phe nol conversion, TOC consumption, the intermediates and the pH variation wit h time have been determined. An irreversible bonding of phenol on the catal yst surface has been found as a previous step to the phenol oxidation react ion. An overall pseudo-first order kinetic constant has been calculated for phenol conversion and values obtained at basic pH are lower than those cal culated for acid pH media. An important homogeneous contribution for the ph enol oxidation rate was found. However, the intermediates mineralization is notably influenced by the catalyst load. (C) 1999 Elsevier Science B.V. Al l rights reserved.