Catalytic wet air oxidation of phenol in caustic refinery effluents

Phenol, in industrial aqueous effluents, causes serious damage to human health and ecosystems due to its high toxicity. Catalytic wet air oxidation (CWAO) is a process that effectively transforms phenol into compounds with lower environmental impact. The development of catalysts capable of operating continuously without activity loss in industrial effluents is a challenge due to metal leaching deactivation caused by the formation of organic acids during oxidation reactions. In particular, effluents from caustic treatments in refineries extract large amounts of phenol and their treatment by CWAO has not been widely addressed. In the present study, CuO and ZnO catalysts were synthesized by employing different aluminum-based supports, which not only achieved high phenol oxidation in neutral aqueous solutions, but also increased the phenol degradation degree with great stability in a refinery sample from caustic treatment, making CWAO viable for processing industrial effluents.