Synthesis of MIL-101(Cr) Metal Organic Framework by Green Synthesis for CO₂Gas Adsorption

Global warming issue due to the excessive carbon dioxide gas emission have raised strong interest in capturing or reducing the CO2 from flue gas or atmosphere. Physisorption-based CO2 capture applying the metal organic framework (MOF) provides a promising alternative for capturing CO2 due to the simplicity, low operating cost, and low energy requirement of the adsorption approach combined with the high CO2 adsorption capacity MOF material. In this study, a series of Chromium based MIL MOF with a variety molar ratio of chromium metal to 1,4-Benzene Dicarboxylate (BDC) organic linker were prepared via the solvent-free method (mechanochemical) to develop a clean and efficient way of synthesising MOF samples as promising CO2 adsorbents. The XRD results and FTIR spectra have confirmed the successful fabrication of MIL-101(Cr) MOF using the solvent-free method. The SEM images illustrated fine growth of irregular shaped coarse particles for Cr MOF with equal mole ratio of Cr to BDC. The MIL-101(Cr) samples were also tested on their CO2 adsorption capacity to understand the influence of molar ratio of the starting materials on the CO2 adsorption capacity. It was found that the MIL-101(Cr)1 led to the formation of a product with the highest CO2 uptake capacity of 18.78 mmol/g. In contrast, the EDS analysis result revealed that all the samples synthesised in this work were well incorporated with the Chromium element. It is therefore suggested that the molar ratio of Cr to BDC plays a critical role in determining the CO2 gas adsorption capacity.