Visible Light Photocatalytic Degradation of Methylene Blue Using Polypyrrole-Coated Molybdenum-Based Magnetic Photocatalyst

In this study, Ppy@MoO3@Fe3O4 photocatalyst was used to degrade methylene blue (MB) under visible light irradiation. The optimum catalyst loading, initial MB dye concentration, and solution pH was found to be 500 ppm, 40 ppm, and pH 5, respectively, and resulted to 94.1% MB dye degradation within 90 min irradiation. The mineralization of MB obtained 93% TOC removal. Pseudo-first order kinetic model governed the degradation of MB having a rate constant of 0.027 min-1. Furthermore, it was demonstrated that h+ and O2 species played a critical role in the visible light photocatalytic degradation of MB. The Ppy@MoO3@Fe3O4 photocatalyst also showed better photocatalytic performance on MB dye degradation compared to MoO3@Fe3O4 and controls. Finally, the Ppy@MoO3@Fe3O4 photocatalyst exhibited consistently high performance even after 4 cycles, proving that the as-prepared nanomaterial can be considered as a promising photocatalyst with good photocatalytic activity, stability, and reusability.