Catalytic wet air oxidation of carboxylic acid present in wastewater

Abstract

Catalytic Wet Air Oxidation (CWAO) of acrylic acid, a representative of carboxylic acids, was carried out in a pressurized reactor at a partial pressure of air (4 kg/cm²) and temperature (140-180°C) to reduce the COD of wastewater containing acrylic acid. Catalysts tested include both homogeneous (CuSO₄ and FeSO₄) and heterogeneous [Co: Bi (5:1) and Mn: Ce (1:1)] catalysts. Catalytic activity of Mn: Ce (1:1) at 5g/l was best with 86% COD reduction at 180°C and air partial pressure 4 kg/cm² in 6 h. Initial pH of the solution has strong effect on COD reduction. Reaction kinetics of wet air oxidation of acrylic acid fitted well a first order kinetics with respect to COD of acrylic acid. Catalysts activity was correlated in terms of the physical characteristics.