Green Synthesis of MOF-801(Zr/Ce/Hf) for CO₂/N₂ and CO₂/CH₄ Separation

Abstract

The\npurification of natural gas and the removal of carbon dioxide\nfrom flue gases are crucial to economize precious resources and effectively\nrelieve a series of environmental problems caused by global warming.\nMetal–organic framework (MOF) materials have demonstrated remarkable\nperformance and benefits in the area of gas separation; however, obtaining\nmaterials with high gas capacity and selectivity simultaneously remains\ndifficult. In addition, harsh synthesis conditions and solvent toxicity\nhave been restricted in large-scale production and industrial application.\nTherefore, MOF-801(Zr/Ce/Hf) was created based on the green synthesis\nof the MOF-801 construction unit by altering the kinds of metal salts,\nand the impact of three metal nodes on the performance of gas adsorption\nand separation was demonstrated by contrasting the three MOFs. The\nresults showed that MOF-801(Ce) has the best CO₂ adsorption\ncapacity (3.3 mmol/g at 298 K), which also was demonstrated with in\nsitu diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)\nresults, CO₂/CH₄ (ideal adsorbed solution theory\n(IAST) = 13.28 at 298 K, 1 bar, CO₂/CH₄ = 1:1,\nv/v), and the separation performance of CO₂/N₂ (IAST = 57.46 at 298 K, 1 bar, CO₂/N₂ = 1:1,\nv/v) among the group. Green synthesis of MOF-801(Zr/Ce/Hf) is an ideal\ncandidate for flue gas separation and methane purification because\nof its high regeneration capacity and strong cyclic stability.