Water-based synthesis of zeolitic imidazolate framework-8 for CO2 capture

Abstract

This paper studies the impacts of five key synthesis parameters of zeolitic imidazolate framework-8 (ZIF-8) in an aqueous solution, namely zinc resource, pH value, temperature, reaction time, and the concentration of water in the ligand (H₂O/Hmim). It was found that the crystallization of ZIF-8 samples is strongly impacted by these synthesis parameters. ZIF-8 synthesized at a temperature of 85 °C, reaction time of 5 min, and pH value of 11.4 had a large special surface area and pore volume, and thus had a high CO₂ adsorption capacity of 3.04 mmol g⁻¹. The CO₂ capture capacity remained constant after eleven consecutive adsorption–desorption experiments. Further applications of the hydrothermal synthesis method are promising considering the remarkable CO₂ adsorption capacity and cyclic regeneration ability.