Photocatalytic degradation of ketoconazole by Z-scheme Ag3PO4/graphene oxide: response surface modeling and optimization.

Ketoconazole is an imidazole fungicide which is commonly used as pharmaceutical and healthcare products. Residual amount of this compound can cause adverse ecological health problems. The present study investigated ketoconazole photocatalytic degradation using Ag3PO4/graphene oxide (GO). Ag3PO4/GO and Ag3PO4 as visible light-driven photocatalysts was synthesized using the in situ growth method. Degradation of ketoconazole at the concentration of 1-20 mg/L in aqueous solutions was optimized in the presence of Ag3PO4/GO nanocomposite with the dosage of 0.5-2 g/L, contact time of 15-20 min, and pH of 5-9 using response surface methodology. A second-order model was selected as the best fitted model with R2 value and lack of fit as 0.935 and 0.06, respectively. Under the optimized conditions, the Ag3PO4/GO catalyst achieved a photocatalytic efficiency of 96.53% after 93.34 min. The photocatalytic activity, reaction kinetics, and stability were also investigated. The results indicated that the Ag3PO4/GO nanocomposite exhibited higher photocatalytic activity for ketoconazole degradation, which was 2.4 times that of pure Ag3PO4. Finally, a direct Z-scheme mechanism was found to be responsible for enhanced photocatalytic activity in the Ag3PO4/GO nanocomposite. The high photocatalytic activity, acceptable reusability, and good aqueous stability make the Ag3PO4/GO nanocomposite a promising nanophotocatalyst for photocatalytic degradation of azoles contaminants.