Challenges of heterogeneous catalytic wet air oxidation processes and potential applications on emerging contaminants loaded wastewater treatment

The heterogeneous catalytic wet air oxidation (Het CWAO) process can be used as a full process or as an additional wastewater treatment for the complete degradation of pharmaceutical pollutants. This investigation includes a critical review of related previous studies, requirements, challenges, limits, and scaling up process of the Het CWAO. We found that most studies focused on decolorization and conversion instead of mineralization to follow catalytic progress. Moreover, very few researchers have assessed successive catalytic cycles, catalyst deactivation, carbon balance, toxicity, and biodegradability which are a key index for Het CWAO assessment. Catalyst stability and durability are the most significant challenges and limitations of Het CWAO which affects the scaling up process. With this review we opt to redirect future research to the development of stable, durable, and cost-effective catalysts for Het CWAO test, where successive catalytic cycles, deactivation, carbon balance, toxicity, and biodegradability analysis are assessment index for targeted wastewater.