Degradation of Organic Pollutants by Wet Air Oxidation Using Nonnoble Metal-Based Catalysts

Abstract

Phenol is a major organic pollutant found in wastewater streams generating from several industries. The presence of excess phenol makes the wastewater unsuitable for conventional biological treatment. The present study was performed to treat synthetic phenolic wastewater by catalytic wet air oxidation (CWAO) at low operating conditions (90–150°C temperature and 0.5 MPa total air pressures). In addition, the degradation of two major intermediates (acetic acid and oxalic acid) was also observed under similar operating conditions. The reaction was performed in a stainless steel (SS-316) high-pressure reactor. Among all homogeneous (CuSO4 and FeSO4) and heterogeneous catalysts (CuO/CeO2 in different proportions: 100/0, 80/20, 60/40, and 50/50), CuSO4 exhibited the best performance with more than 90% reductions in phenol and total organic carbon (TOC) at 120°C temperature within 4 h. CuSO4 showed good capability for the removal of oxalic and acetic acids (TOC reductions were 81% and 67%, respectively). Future studies can be aimed to investigate the catalytic activity of CuSO4 for industrial effluents containing phenol as a major pollutant.