Pd-based catalysts for catalytic wet oxidation of combined Kraft pulp milleffluents in a trickle bed reactor

Catalytic wet oxidation of combined pulp mill effluents was studied in a tr ickle bed reactor. Two types of supported Pd-based catalysts, eggshell and uniform catalysts, and a supported Pd-Pt uniform catalyst were employed. Su pported Pd catalysts showed high activity fur total organic carbon (TOC) an d color removal at temperatures of 353-448 K and 1.84 MPa. Compared to unif orm catalysts, the eggshell catalysts with a 0.2 wt.% Pd loading show promi se for treatment of combined pulp mill effluents. High activity for TOC and color removal can be attributed to the high density of active Pd sites in the shell area and to the decrease of diffusion path for reactants and inte rmediates. No apparent deactivation of eggshell catalysts was observed afte r 40 h on stream. Potential application of the supported Pd catalysts for t reatment of combined pulp mill effluents is discussed. (C) 2001 Elsevier Sc ience B.V. All rights reserved.