Synthesis and photocatalytic degradation of azithromycin by iron/zinc oxide nanoparticlereinforced carbon nanofibers

Abstract

Water pollution caused by persistent pharmaceutical contaminants, such as azithromycin, presents serious public health and environmental challenges. This study introduces iron/zinc oxide-reinforced carbon nanofibers (Fe/Zn-CNFs) synthesized via a scalable electrospinning process as a novel solution for treating pharmaceutical waste streams. The synthesized nanofibers showed a crystalline structure (confirmed by XRD and Raman analyses), an optimized bandgap energy of 2.899 eV (determined by DRS), and an impressive specific surface area of 554 m²/g (measured by BET analysis). Their synergistic photocatalytic activity arises from the effective integration of iron/zinc oxide nanoparticles into the carbon nanofiber matrix. Key parameters influencing azithromycin degradation including pH, reaction time, catalyst concentration, and pollutant concentration were systematically optimized. Under optimal conditions (pH 4, 27.1 mg/L catalyst dose, 15.8 mg/L azithromycin concentration), the nanofibers achieved a remarkable 97.5% degradation of azithromycin within 103 min under UV irradiation. The study further proved the photocatalyst’s versatility, achieving degradation efficiencies of 98% under UV light and up to 85% under visible light, highlighting its ability to utilize diverse light sources. The reusability testing over five consecutive cycles revealed that the Fe/Zn-CNFs maintained over 80% degradation efficiency in the final cycle, underscoring their excellent stability and practical applicability. Beyond photocatalytic efficiency, the nanofibers exhibited notable antibacterial activity against Escherichia coli and Staphylococcus aureus, which can be attributed to the generation of reactive oxygen species (ROS). These results underscore the potential of iron/zinc oxide-reinforced carbon as a sustainable and effective photocatalyst for treating antibiotic-contaminated wastewater, offering a viable approach to modifying environmental antibiotic resistance