Facile fabrication of a novel chitosan/carboxymethyl cellulose/bentonite/CuO nanocomposite for enhanced photocatalytic and antibacterial applications†

In this study, an eco-friendly chitosan/carboxymethyl cellulose/bentonite/CuO nanocomposite (CS/CMC/BN/CuO NC) was synthesized utilizing algal-mediated copper oxide nanoparticles (CuO NPs). The resulting hybrid nanocomposite was thoroughly characterized using advanced techniques, including XRD, FTIR, UV-vis, FE-SEM, HR-TEM, and BET analysis. The photocatalytic activity of the hybrid nanocomposite was assessed by the degradation of brilliant cresyl blue (BCB) dye under visible light irradiation, while the antibacterial activity of the hybrid nanocomposite was evaluated against both Gram-positive and Gram-negative bacterial strains. XRD analysis confirmed the successful synthesis of the hybrid nanocomposite (CS/CMC/BN/CuO NC) with a crystallite size of 9.66 nm. The UV-vis analysis and Tauc plot revealed that the hybrid nanocomposite exhibited an absorbance peak at 249 nm and a band gap of 2.81 eV, respectively. FE-SEM and HR-TEM analysis highlighted its unique broken-tile structure. Furthermore, the hybrid nanocomposite exhibited outstanding photocatalytic performance, achieving 98.38% degradation of BCB dye within 60 min under optimal conditions. The scavenging experiments showed that electrons (e⁻) and superoxide anion radicals (O₂˙⁻) are the major reactive species involved in the degradation of BCB dye. Additionally, it demonstrated remarkable antibacterial efficacy, showing a 40 mm zone of inhibition (ZOI) against the Gram-negative Pseudomonas aeruginosa strain. The findings indicate that the synthesized CS/CMC/BN/CuO NC holds significant promise for the photodegradation of organic dyes. Furthermore, it exhibits strong antibacterial properties, making it a potential disinfectant for treating wastewater contaminated with pathogenic bacteria.