Optimization of carbamazepine photodegradation on defective TiO2-based magnetic photocatalyst

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In this work, carbamazepine (CBZ) degradation over defective Fe 3 O 4 @SiO 2 /d-TiO 2 /Pt photocatalyst was studied. Within the titania structure, Ti vacancies and Pt nanoparticles were introduced to enhance the photocatalyst's light absorption and influence charge carriers' mobility. For the carbamazepine degradation, process parameters, e.g., temperature, flux intensity, photocatalyst loading, aeration, pH, and addition of H 2 O 2, were optimized for 4 or 5 different levels, with the quadratic model including 2-factor interactions determined to analyze the effect of these parameters. Carbamazepine presence and by-product formation were monitored using the HPLC-DAD system together with additional HPLC-TOFMS analysis for further identification of created compounds. Acridine was selected as an additional factor, indicating differences in the performed process of photolysis and photocatalytic CBZ degradation. Pure TiO 2 exhibited the highest efficiency of CBZ degradation under alkaline conditions, while the performed optimization shows that a combination of H + and H 2 O 2 addition is crucial to achieve high CBZ removal and its mineralization in the presence of Fe 3 O 4 @SiO 2 /d-TiO 2 /Pt photocatalyst. The obtained results were discussed concerning photocatalyst structure, generation of reactive oxygen species inside H + /H 2 O 2 /photocatalyst system, and the possible effect of introduced Ti vacancies. In terms of reusability, the performance of Fe 3 O 4 @SiO 2 /d-TiO 2 /Pt photocatalyst was stable after 8 subsequent cycles of carbamazepine degradation.