Catalytic Wet-Air Oxidation of Aniline Removal from Synthetic Wastewater

Wet-air oxidation (WAO) and catalytic wet-air oxidation (CWAO) over CuO/Al2O3 and NiO/Al2O3 catalysts for aniline removal were investigated. The oxidation reaction was carried out in a 1000-ml high-pressure batch reactor. The temperatures of 160, 200 and 260C and the pressures of 5 and 10 bars were generally applied for 120 min. CuO/Al2O3 and NiO/Al2O3 catalysts were prepared by impregnation method. It is found from the results that aniline was completely degraded at these conditions. However, aniline was converted into other organic carbons which remained in the solution. So COD was found in the solution after the reaction. It is seen from the results that 56% of COD was removed by WAO at 200C and 10 bars for 120 min. The CWAO over CuO/Al2O3 catalyst showed higher COD removal (76%) than NiO/Al2O3 catalyst (60%). The types of metal oxide had an effect to the activity of COD removal; that is, CuO showed higher COD removal than NiO. The WAO and CWAO of COD removal in aniline solution were the first-order kinetic with the constant reaction rate and activation energy for CuO/Al2O3 of 0.234 s-1 and 11.772 kJ/mol, respectively.