Catalytic Wet Air Oxidation of Pulp and Paper Industry Wastewater

Paper bleaching effluent was treated by catalytic wet oxidation method and the effect of the type of the catalyst on the efficiency was investigated. Cerium oxide, cobalt oxide and copper oxide based (CuOx-CoOx-CeO2) composite catalysts which were varying with regard to CuOx, CoOx and CeO2 compositions were prepared by co-precipitation method. The efficiency of the process was determined by measuring the chemical oxygen demand (COD), total organic carbon (TOC), adsorbable organic halides (AOX) and Cl− removal yields. When the COD, TOC and AOX removal yields were considered, better results were achieved with copper and ceria based catalysts than the cobalt based catalysts. At the optimum reaction conditions (T—473 K, t—120 min, P—130–250 psig), the maximum removal yields obtained by the 50% CuOx–50% CeO2 catalyst. When the wastewater of the I stage of paper bleaching process was treated, removal yields of TOC, COD and AOX were detected as 89; 94 and 95%, respectively Whereas, removal yields of 53% COD, 84% TOC, 90% AOX and 76% Cl− were achieved for the III stage wastewater. It was shown that removal of the toxicity of wastewater samples that were collected from the paper bleaching process by the proposed treatment methods.