Innovative RGO-bridged S-scheme CuFe2O4@Ag2S heterojunction for efficient Sun-light-driven photocatalytic disintegration of Ciprofloxacin

Abstract

Antibiotics contamination in water bodies poses a significant threat to public health and the environment, necessitating advanced methods for their removal from wastewater. In response to this issue, developing a novel magnetic nanocomposite (RGO/CuFe2O4@Ag2S) as an efficient photocatalyst for the degradation of pharmaceuticals like ciprofloxacin (CIP) is of great importance. The synthesized nanocomposite underwent comprehensive characterization to elucidate its crystalline structure, chemical bonding, surface morphology, elemental composition, internal structure, optical properties, surface area, particle size distribution, and magnetic properties. Under optimized conditions (pH=9, nanocomposite dose =0.5 g/L, CIP concentration of 20 mg/L, and duration of 200 minutes), the nanocomposite demonstrated complete degradation of CIP. Moreover, post-treatment analysis revealed significant reductions in total organic carbon (TOC) and chemical oxygen demand (COD) of 70.08% and 85.08%, respectively, indicating extensive mineralization of the antibiotic. Mechanistic investigations revealed a unique S-scheme heterojunction in the RGO/CuFe2O4@Ag2S nanocomposite, where RGO acts as an electronic bridge between CuFe2O4 and Ag2S. This innovative architecture facilitates efficient charge separation and transfer, significantly enhancing the photocatalytic activity. Reusability tests demonstrated the robust nature of the photocatalyst, with only a modest 6% decline in efficiency after six consecutive cycles. To further assess the system's effectiveness in real-world applications, its performance was evaluated in treating pharmaceutical wastewater. The biodegradation efficiency was quantified by measuring the Average Oxidation State (AOS) and Carbon Oxidation State (COS) of the wastewater samples before and after treatment.