CuS/chitosan composite: dual function material for visible-light driven methylene blue dye degradation and bacterial...

This study reports the hydrothermal synthesis, characterization, and multifunctional performance of CuS/chitosan composites for the photocatalytic degradation of methylene blue (MB) dye under visible light and antimicrobial applications. The hydrothermal approach enabled the successful integration of CuS nanoparticles into the chitosan matrix, enhancing the crystallinity and morphology of the composite. The average crystallite size of the CuS/chitosan composite was found to be 20.8 nm, smaller than that of pure CuS (24.4 nm), indicating a stabilizing effect from the biopolymer. SEM analysis revealed that CuS nanoparticles are well-dispersed on the chitosan surface, while elemental mapping confirmed a high copper content (CuS) and significant carbon presence (chitosan incorporation). The CuS/chitosan composite achieved complete degradation of MB dye under visible light, outperforming bare CuS (84% degradation), and demonstrated good reusability over six cycles. Furthermore, the composite exhibited strong antibacterial activity against Escherichia coli (19 mm inhibition zone) and Streptococcus aureus (20 mm), underscoring its promise for environmental remediation and biomedical applications.