Efficacy of Fresh and Used Supported Copper-Based Catalysts for Ferulic Acid Degradation by Wet Air Oxidation Process

Pulp mill effluents are not suitable for conventional biological treatment processes due to the presence of lignin which is found in cellulosic raw materials. The present study was undertaken to remove ferulic acid (a lignin model compound) from synthetic wastewater using a catalytic wet air oxidation (CWAO) process. The hydrothermal process was performed in the presence of three heterogeneous catalysts, namely, 60% CuO/40% CeO2, 60% CuO/40% Al2O3, and 60% CuO/40% 13X, in a temperature range of 90-160 degrees C, while the total pressure was maintained in the range of 0.55-0.8 MPa. CuO and CeO2 mixture (prepared by the sol gel peroxo method) exhibited the best performance and removed ca. 70% chemical oxygen demand (COD) from the wastewater at 120 degrees C temperature. The spent catalyst showed appreciable decline in the COD removal during reuse. The detailed results obtained from the catalyst characterization (fresh and used) and WAO studies are presented in the paper.