Enhancing environmental remediation: sustainable photocatalytic degradation of water pollutants with biodegradable chitosan–ZnO nanocomposites

This study presents the eco-friendly synthesis and characterization of chitosan–ZnO hybrid biocomposites, utilizing chitosan extracted from tiger prawn shells as a natural polymer matrix for encapsulating zinc oxide nanoparticles (NPs). The biocomposites were synthesized through environmentally friendly processes and characterized by FTIR, X-ray diffraction (XRD), and SEM coupled with EDS. Photocatalytic assessments were conducted under UV and visible light against organic dyes methylene blue (MB), toluidine blue, and bromophenyl blue. The results indicated that ZnO NPs degraded MB, toluidine blue, and bromophenyl blue with efficiencies of 74.8%, 87.5%, and 97.4%, respectively. Chitosan–ZnO NPs and chitosan–ZnO/PVA NPs demonstrated varied efficiencies, with the latter showing superior performance across all dyes, achieving degradation efficiencies of 82.2% for MB, 87.8% for toluidine blue, and 99.01% for bromophenyl blue in 10 min. These results shows the improved photocatalytic activity of the nanocomposites, especially with chitosan–ZnO/PVA NPs, which employing their possible use in dyes removal and environmental remediation projects. This work emphasizes the feasibility of chitosan-based biocomposites as an efficient photocatalysts, therefore supporting sustainable material development in ecological uses.