Sustainable Cu@CoFe2O4/SGCN Heterojunction Photocatalysts for Solar-Driven Degradation of Methylene Blue and Antifungal Potential

Abstract

Ecosystems and people are in danger from organic dye contamination in water bodies, which calls for creative approaches to water purification. Using a straightforward co-precipitation technique, we synthesized a new copper-doped cobalt ferrite composite with sulfur-doped graphitic carbon nitride (Cu@CoFe₂O₄/S-g-C₃N₄) heterojunction nanocomposite in this work. The composite was systematically characterized using XRD, FTIR, BET surface area analysis, SEM, TEM, UV-Vis DRS, and PL spectroscopy to reveal its structural and optical properties. BET analysis confirmed a surface area of 85.4 m²/g, contributing to improved photocatalytic action. The photocatalytic efficiency was assessed using methylene blue (MB) as a model pollutant under solar radiation. Among the synthesized materials, the optimized Cu@CoFe₂O₄/S-g-C₃N₄ NC demonstrated outstanding performance, achieving 97% degradation of MB within 120 min, with a degradation rate constant of 0.032 min⁻¹, approximately 3.5 times higher than pristine g-C₃N₄ (0.009 min⁻¹) and 2.8 times higher than Cu@CoFe₂O₄ (0.011 min⁻¹). The effective charge carrier separation made possible by the heterojunction interface and the enhanced light absorption brought about by the combined effects of Cu doping and the integration of CoFe₂O₄ and S-g-C₃N₄ are responsible for this astonishing improvement. Stability and reusability tests confirmed the Nanocomposite retained 91.6% of its photocatalytic efficiency after five cycles, highlighting its robustness and potential for long-term application. The cost-effectiveness, environmental compatibility, and scalability of the Cu@CoFe₂O₄ /S-g-C₃N₄ make it a favorable intranet for industrial wastewater treatment. The highest antifungal activities of Cu@CoFe₂O₄ /S-g-C₃N₄ were estimated to be 36.7 mm, 39.4 mm, and 43.3 mm versus C. gloeosporioides, E. salmonicolor and C. albicans, respectively. This study underscores the potential of heterojunction-based photocatalysts in sustainable water purification, providing a pathway for tackling organic dye pollution. Future research will focus on extending this approach to address other emerging organic contaminants, further advancing global efforts in environmental remediation.