Degradation behaviors of naproxen by a hybrid TiO2 photocatalyst system with process components

[Display omitted] •The degradation of naproxen was studied in a hybrid TiO2 photocatalytic system.•Operating conditions were varied for single process and fixed for multiple processes.•The degradation efficiency was improved only within certain limits for unit process.•A combination of multiple processes remarkably increased the degradation efficiency.•Two preferred routes were recommended for the photocatalytic degradation pathway. A hybrid system combining microwave and a microwave discharge electrodeless lamp (MDEL) was proposed to overcome the limitations of conventional TiO2 photocatalysts. The degradation efficiency and mechanism of naproxen were determined using a series of single processes, including conventional TiO2 photocatalyst reactors and a hybrid system that fuses them. Although the degradation efficiency tended to increase after changing the experimental condition of a single process, the optimal conditions existed for these experimental conditions. On the other hand, remarkable synergy was observed in the fused process, whose efficiency was significantly higher than that of the unit process. In particular, the optimal degradation ability was obtained by adding hydrogen peroxide together with microwave irradiation. The seven intermediates in the proposed photocatalytic degradation pathway were generated by the demethylation and hydroxylation by hydroxyl radicals. These results are expected to provide new data on the design of high efficiency photocatalytic systems at low cost.