Exploration of the photocatalytic activity of various zeolitic imidazolate frameworks (ZIF-8, ZIF-9, ZIF-67, and Co-ZIF-L) on organic dye crystal violet

Photocatalysts have emerged as outstanding materials for the elimination of different types of contaminants from the aquatic environment. This research paper presents a thorough comparative assessment of various Zeolitic imidazole frameworks (ZIFs) to study their efficiency in the degradation of crystal violet (CV) dye. ZIF-8, ZIF-67, and Co-ZIF-L were synthesized by the solution mixing method, and ZIF-9 by the hydrothermal method. The synthesized ZIF samples were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectrophotometer, field emission scanning electron microscope (FESEM), and ultraviolet–visible (UV–Vis) Spectroscopy. Morphological studies carried out using FESEM revealed distinct features. ZIF-8 displayed rhombic dodecahedra, ZIF-9 and ZIF-67 formed uniform polyhedral structures, while Co-ZIF-L exhibited a leaf-like structure. The photocatalytic study was conducted under dark and light conditions for the adsorption and degradation of CV dye. An extensive examination of degradation rate kinetics and pollutant removal efficiency was performed to understand the strengths and limitations of ZIFs for facilitating the development of highly efficient and sustainable wastewater treatment processes. Among all synthesized samples, ZIF-8 shows maximum degradation efficiency (~ 77%), follows second-order rate kinetics with a rate constant of 0.2117 g/(mg min), towards the degradation of CV from wastewater. Mott-Schottky and scavenger experiments confirmed that ZIF-8 is much better than other ZIFs, as it can generate more hydroxyl radicals (•OH) under light illumination. This demonstrates the potential of ZIF-8 as a highly efficient photocatalyst for wastewater treatment applications, fulfilling the objective of developing a sustainable and high-performance material.