Response surface optimization of the photocatalytic degradation of atenolol using immobilized graphene‐TiO 2 composite

Photocatalytic processes using semiconductors have been widely explored due to their fascinating benefits in environmental remediation. In this study, a four‐factor three‐level Box‐Benkhen design (BBD) was employed to assess the photocatalytic degradation of atenolol (ATL) using immobilized graphene‐TiO 2 as a photocatalyst. The four variables that were considered in the BBD model were the photocatalyst concentration (10%‐20%), pH (4‐9), ATL concentration (10‐30 mg/L), and light intensity (60‐260 W/m 2 ). A monolithic‐type swirl‐flow reactor, which allowed the immobilization of the photocatalyst, was employed in a semi‐batch system to study the photocatalytic degradation kinetics of ATL. The optimum conditions where the highest rate constant (0.667 min −1 ) was observed were graphene‐TiO 2 concentration of 10%, pH of 6.5, ATL concentration of 30 mg/L, and light intensity of 160 W/m 2 . The developed model well predicted the observed values indicated by a high R 2 of 0.897. Reaction rate constants obtained herein using graphene‐TiO 2 in immobilized form were compared with slurry system and TiO 2 .