Microwave-assisted synthesis of Mg-gallate for efficient CO2 capture

Abstract

With the development of modern industry and increasing population around the world, the overuse of fossil fuels for energy supply has produced large amounts of CO2 in the atmosphere. Metal-organic frameworks (MOFs) with tailorable structures and developed porosity have emerged as promising candidates for CO2 adsorption and separation. However, the synthesis of MOFs by conventional hydrothermal method faces challenges like low crystallization rate and yield, which limits their industrial application for gas adsorption. In this work, a highly efficient microwave (MW)-assisted method was employed for the synthesis of Mg-gallate. The effects of MW conditions on the structure, morphology, and CO2 adsorption properties of Mg-gallate were systematically investigated. The highest CO2 adsorption performance (5.37 mmol g−1 at 298 K and 1 bar) was achieved on the Mg-gallate synthesized at 100 °C for 20 min under an MW power of 100 W. The obtained Mg-gallate also exhibited high adsorption selectivity of CO2 over N2 (1500) and superior recyclability. Furthermore, the Mg-gallate@PEI composite beads were designed by incorporating the MOF crystals into the polymeric matrix in order to satisfy the industrial application demands. The combined advantages of rapid MW synthesis, excellent adsorption performance, and shaping make the Mg-gallate a promising material for practical CO2 capture.