Oxygen activation and transfer for catalytic wet-air oxidation of wastewater: a short review

With the rapid growth of population and industrial production, wastewater pollution has become a major environmental issue. Wastewater pollution also poses a threat to water resources and human health. Catalytic wet-air oxidation (CWAO) is one of the most economical and environmentally friendly technologies, especially for the treatment of toxic and non-biodegradable pollutants in wastewater. Various heterogeneous catalysts have been reported for use in wastewater treatment; however, most of these catalysts are effective only under high temperatures and high pressures. The increasing demand for the removal of wastewater pollutants necessitates the development of low-temperature, high-efficiency catalysts for CWAO technology. To achieve this, the ability of the catalyst to activate O₂ and transfer active oxygen species plays a key role in determining the catalytic performance. In this review, we summarize recent advances in various noble and non-noble metal catalysts, oxide catalysts and carbon catalysts for CWAO reactions, focusing on the positive effect of O₂ activation and transfer on catalytic performance. We also propose future directions for developing novel CWAO catalysts by optimizing the catalyst's ability to activate O₂ and transfer active oxygen species.