Investigation of photocatalytic degradation of methyl orange using zinc oxide-supported chitosan hydrogel beads

In this study, chitosan-based ZnO supported hydrogels (CZ–H) were synthesized to evaluatetheir photocatalytic degradation performance against methyl orange (MO) dye. The compos-ite hydrogels were characterized using X-ray Diffraction (XRD), UV–Vis DRS, ScanningElectron Microscopy (SEM-EDS), Thermogravimetric Analysis (TGA), and Fourier TransformInfrared Spectroscopy (FTIR). These characterization results confirmed the successful forma-tion of the CZ–H composite structure. The band gap of the composite was approximately2.77 eV, supporting enhanced photocatalytic activity. Photocatalytic experiments showedthat CZ–H removed 74% of MO within 60 min, compared to 42% for pure chitosan beads,with reaction rate constants of 0.0237 min−1 and 0.0113 min−1, respectively. Moreover, theCZ–H beads demonstrated good reusability with minimal loss in efficiency over multiplecycles. These findings highlight the potential of CZ–H as a stable, effective, and reusablephotocatalyst for the efficient removal of dyes from wastewater.