Response surface optimization of the photocatalytic degradation of atenolol using immobilized graphene‐TiO2 composite

Abstract

AbstractPhotocatalytic 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‐TiO2 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/m2). 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‐TiO2 concentration of 10%, pH of 6.5, ATL concentration of 30 mg/L, and light intensity of 160 W/m2. The developed model well predicted the observed values indicated by a high R2 of 0.897. Reaction rate constants obtained herein using graphene‐TiO2 in immobilized form were compared with slurry system and TiO2.