Oxidation catalysts prepared from biosorbents supported on zeolites

The catalytic oxidation of 1,2-dichlorobenzene was investigated over NaY and NaX zeolites, loaded with chromium through the action of a robust biosorption system consisting of a bacterial biofilm supported on the zeolites. The results of biosorption showed that the maximum metal removal efficiency was 20%, in both systems based on NaY or NaX, starting from solutions with chromium(VI) concentrations ranging from 50 to 250 mg(Cr)/L. The bacterial biofilm, Arthrobacter viscosus, supported on the zeolite reduces Cr(VI) to Cr(III). The Cr(HI) is retained in the zeolite by ion exchange. The new catalysts were characterized by spectroscopic methods (FTIR), chemical analyses (ICP-AES), surface analysis (XRD) and thermal analysis (TGA). The various techniques of characterization show that this biosorption process does not modify the morphology and structure of the FAU-zeolites. These catalysts, Cr/FAU, prepared through this new procedure present good activity and selectivity for dichlorobenzene oxidation in wet air at 350 degrees C. The Cr-50-Y was selected as the most active, selective and stable catalyst for oxidation of 1,2-dichlorobenzene in wet air. (c) 2006 Elsevier B.V. All rights reserved.