Comparative optimization of the photocatalytic degradation of azithromycin using cerium oxide nanoparticles synthesized from chemical and natural sources: Sustainability assessment

Abstract

Antibiotics in wastewater have become a significant environmental concern, contributing to the emergence of antibiotic-resistant microorganisms and posing a growing threat to global public health. This study comparatively evaluated the effectiveness of biosynthesized and chemically synthesized CeO2 nanoparticles (CeO2NPs) for the degradation of azithromycin (AZI), one of the most frequently detected antibiotics in aquatic environments. The biosynthesized CeO2NPs were prepared using fresh Psidium guajava L. leaves. The response surface methodology, using Box–Behnken experimental design was employed to optimize the critical factors influencing the photodegradation of AZI; as initial concentration of AZI, agitation rate, pH, the contact time, the type and amount of CeO2NPs. The biosynthesized CeO2NPs demonstrated a remarkable removal efficiency of 98.6% at pH 7 and contact time of 5 h under lamp irradiation, significantly exceeding that of the chemically synthesized CeO2NPs. Additionally, the greenness profile of the solvents used was evaluated using the Greenness Index Tool and the nanomaterials performance and synthesis sustainability was assessed by the newly introduced Nanomaterials Assessment Tool (NAT). The recyclability and reusability of the biosynthesized nanoparticles were evaluated, demonstrating consistent efficiency and promising potential for water treatment applications. These findings demonstrate the significant potential of the biosynthesized CeO2NPs for mitigating antibiotic pollution, particularly in strategies aimed at combating bacterial resistance, while also promoting sustainable practices in nanotechnology applications.