Optimization of aqueous p-aminophenol degradation by external-loop airlift sonophotoreactor using response surface methodology

► Combined photolysis and sonolysis were employed in an external-loop airlift reactor. ► Degradation of p-aminophenol (PAP) and TOC removal rates were studied under different processes. ► The effects of various parameters were studied using response surface methodology. ► The PAP and TOC removal rates were modeled as functions of different factors. ► A genetic algorithm was used to maximize the TOC removal efficiency.