Synthesis of zeolitic imidazole framework-8 derived ZnCo layered double hydroxides for the removal of methylene blue from wastewater

The development of highly efficient and cost-effective materials for water treatment is paramount and the preparation of metal-organic framework-derived layer double hydroxide (MOF-LDH) is an area of great interest. In this study, an innovative adsorbent material zeolitic imidazole framework-8 (ZIF-8) derived ZnCo layered double hydroxides was prepared by in situ growth for the adsorption of cationic methylene blue (MB) dye from wastewater. Analytical tools such as FTIR, SEM, and XRD were used to characterize the composite material. Different adsorption parameters like initial dye concentration, pH, temperature, contact time, adsorption mechanisms, and density functional theory (DFT) mechanisms were studied which showed that the derived material significantly enhanced the adsorption capacity which was 502.51 mg/g at pH 11. DFT analyses suggested that MB possessed interaction sites favorable to adsorbent material. The adsorption kinetic model showed that pseudo-second-order had a good correlation coefficient (R-2 = 0.99983) value proposing the chemisorption adsorption phenomenon. Both the Langmuir and Freundlich isotherm models are well fitted in experimental data as both have good correlation coefficient (R-2 = 0.99771) and (R-2 = 0.99856) values respectively but the best fit of the adsorption isotherm data was achieved with the Freundlich model, indicating multilayer adsorption characteristics. The experimental and theoretical analyses demonstrated that the fabricated adsorbent is a highly efficient material for the adsorption of organic pollutants from an aqueous medium.