Development and Characterization of Environmentally-Friendly Magnetically Graphene Oxide-Embedded Chitosan as a Recyclable Heterogeneous Photocatalyst

The textile industry has significant environmental impacts, and employing physical, chemical, and biological technologies is crucial for sustainable treatment strategies. Photocatalytic degradation is a straightforward and important technique. This study investigated the photodegradation of textile wastewater, Reactive Red 198 and Blue 133 dyes using magnetic graphene oxide embedded on a chitosan matrix under UV and visible light. Magnetite nanoparticles were prepared via the co-precipitation method of a solution containing Fe2+ and Fe3+ ions under alkaline conditions. Then, magnetic nanoparticles were modified with graphene oxide and chitosan under ultrasound to enhance photoresponse. Characterization included FT-IR, Raman spectroscopy, XRD, zeta potential, DRS, VSM, TGA, DTA, BET, SEM, EDS, and TEM. Optimization of parameters such as pH, photocatalyst quantity, dye concentration, and irradiation time was performed. Under optimal conditions, Reactive Red 198 removal efficiencies were 77.91%, 90.95%, and 95.01% for magnetite, magnetic graphene oxide, and magnetic graphene oxide/chitosan, respectively. Blue 133 removal efficiencies were 48.15%, 66.6%, and 82.1% for the same compounds. After three days of visible light exposure, Reactive Red 198 removal percentages were 79.46%, 90.36%, and 94.75%, and Blue 133 removal percentages were 70.15%, 72.6%, and 90.85% for magnetite, magnetic graphene oxide, and magnetic graphene oxide/chitosan, respectively. The second-order kinetic model demonstrated high accuracy with R2 values of 0.997 and 0.998 for Red 198 and B133 removal, respectively, when applied to magnetic graphene oxide/chitosan. The nanocomposite's reusability was assessed over three cycles, and after two cycles, the removal percentage remained high at approximately 83.96% and 77.66%.