A Comparative Analysis of Solar Photocatalytic Degradation of MB, RhB, and CV Dyes with Zinc Oxide Nanoparticles

Abstract This study successfully synthesized pure ZnO nanoparticles via a straightforward co-precipitation method and thoroughly characterized them to confirm their structural integrity and photocatalytic potential. X-ray diffraction (XRD) patterns revealed sharp peaks consistent with the hexagonal wurtzite phase, indicating excellent phase purity and crystallinity. Raman spectroscopy further supported these findings by displaying the characteristic vibrational modes of ZnO without any impurity signals. High-resolution TEM imaging showed clear lattice fringes, and selected area electron diffraction (SAED) confirmed the polycrystalline nature of the material through well-defined diffraction rings. The photocatalytic activity of the synthesized ZnO was evaluated under natural sunlight against three common organic dyes: Methylene Blue (MB), Rhodamine B (RhB), and Crystal Violet (CV). UV–Visible spectroscopy indicated a gradual reduction in dye concentrations, with kinetic analysis following a pseudo-first-order model. Notably, degradation efficiencies reached 98% for MB, 93% for RhB, and 96% for CV within 160 minutes. These results underscore the efficacy of co-precipitated ZnO as a low-cost, environmentally friendly photocatalyst, offering significant promise for practical wastewater treatment applications.