Magnetic graphene oxide-zinc oxide nanocomposite for enhanced photocatalytic degradation of azithromycin under normal sunlight.

During the Covid-19 pandemic and its aftermath, there has been a sudden surge in the production and consumption of macrolide antibiotics. This surge has had a significant impact on water quality, leading to concentrations exceeding acceptable limits. To address this concerning issue, a magnetic graphene oxide-zinc oxide nanocomposite (MZG) was synthesized using a straightforward wet chemical synthesis method. The synthesized catalyst was then subjected to comprehensive characterization using sophisticated techniques including HRTEM, XRD, FTIR, Raman spectroscopy, BET, XPS, VSM, DRS, and TGA. Subsequently, the MZG photocatalyst's efficacy was evaluated through a series of experiments aimed at degrading azithromycin drug residues in water. These techniques divulged substantial information about the morphology, polycrystallinity, size (in nm range), functional groups, defects, surface area (132.9 m/g), elemental composition (C, O, Fe and Zn), super paramagnetism (Ms 69.78 emu/g), suitable bandgap (2.8 eV) and thermal stability of the material, respectively. The optimized concentration of MZG photocatalyst demonstrated remarkable potential for photocatalytic degradation, particularly towards higher concentrations of 50 ppm azithromycin. It achieved an impressive degradation efficiency of 96.04 % in water when exposed to normal sunlight for just 1 h. Kinetic studies revealed a first-order reaction rate, with a notably higher rate constant (k = 0.0533 min⁻) compared to other photocatalysts. Furthermore, MZG had shown better recyclabilty up to four cycles with minimal loss of photocatalytic acitvity to only 9%. Thus, it proves to be both effective and cost-efficient, capable of functioning under visible radiation. This makes it suitable for industrial applications aimed at removing azithromycin drugs and promoting a safer and more sustainable environment.