The degradation of environmental contaminants using sustainable solar energy is one of the most promising applications of the photocatalytic process. In this research, the individual and interaction effects of persulphate (PS) and peroxymonosulphate (PMS) oxidants on the solar photocatalytic degradation of cortisone acetate (CA) were studied. Concentrations of PS, PMS, and photocatalyst were independent variables, and the response was CA degradation efficiency. Response surface methodology (RSM) and artificial neural network (ANN) models were developed to predict the CA degradation efficiency. The analysis of the current results revealed that the optimum amounts of individual variables were highly affected by the other variables, which confirmed their significant interaction effect. As an example, by increasing the PS concentration, not only were the required concentrations of PMS and photocatalyst decreased, but also the degradation efficiency was enhanced. Then, the overall optimum concentration of the photocatalyst, PS, and PMS were found to be respectively 328.7, 119.1, and 194.2 mg/L using the genetic algorithm method. The maximum CA degradation efficiency at the optimum condition was 95.6% after only 30 min of solar radiation. Finally, investigation of relative importance of the variables showed that the concentrations of both oxidants affected the degradation efficiency almost equally.

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