Photocatalytic removal of pharmaceutical substance by TiO2-coated ceramic beads: Optimization via Box-Behnken Design

The present study aims at developing and optimizing a novel and efficient advanced oxidation process (AOP) for the efficient and rapid elimination of Paracetamol (PCT) in wastewater through photocatalysis using immobilized titanium dioxide nanoparticles (TiO 2 NPs). TiO 2 NPs were efficiently attached to porous ceramic beads to create a heterogeneous photocatalytic system with a view to overcoming the difficulties related to separation of solid powders. The photodegradation experiment on a model drug was conducted using UV light as a source of energy. Parameters affecting the photocatalytic oxidation process were optimized by means of the Box-Behnken Design (BBD) response surface methodology (RSM). The major parameters considered included pH, initial concentration of PCT, concentration of hydrogen peroxide (H 2 O 2 ) and contact time. The model developed from the results of BBD correlated well with the experimental findings and provided significant quadratic mathematical models for predicting removal efficiency. Through ANOVA analysis, the optimal conditions for maximizing the removal efficiency were identified as resulting in 94% removal efficiency after 140 min of contact period. In addition, the photocatalytic treatment exhibited significant mineralization performance for real pharmaceutical wastewater, with TOC and COD removal efficiencies of 79.22% and 40%, respectively, demonstrating the practical applicability of the immobilized TiO 2 /clay bead photocatalyst.