Investigation of Photocatalytic Properties of ZIF- 67, GO/ZIF- 67, and Ni/ZIF- 67 for Crystal Violet Dye Removal

Abstract

This study investigates the photocatalytic degradation of Crystal Violet (CV) dye using Zeolitic Imidazolate Framework-67 (ZIF-67) and its composites, Graphene Oxide/ZIF-67 (GO/ZIF-67) and Nickel/ZIF-67 (Ni/ZIF-67). The materials were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and Ultraviolet–Visible (UV–Vis) spectroscopy, confirming their crystalline structure, morphology, and optical properties. GO/ZIF-67 exhibited exceptional photocatalytic activity, achieving 96.91% degradation of 5 mg/L CV in 36 min under visible light at pH 4 with 0.25 g/L catalyst, following a pseudo-first-order rate constant of 0.94 min⁻¹, compared to 0.91 min⁻¹ for ZIF-67 and 0.64 min⁻¹ for Ni/ZIF-67. This enhanced performance is linked to its reduced bandgap energy of 1.7 eV (vs. 1.93 eV for ZIF-67 and 1.81 eV for Ni/ZIF-67). Parametric studies identified optimal conditions at 2.5–20 mg/L dye concentration and 0.25 g/L catalyst dosage. Reusability tests with GO/ZIF-67 showed 90% efficiency in the first cycle, declining to 23% after four cycles. These findings highlight GO/ZIF-67’s potential as an effective photocatalyst for water remediation.