Solvent-Free Synthesis of MIL-101(Cr) for CO2 Gas Adsorption: The Effect of Metal Precursor and Molar Ratio

Abstract

MIL-101(Cr), a subclass of metal–organic frameworks (MOFs), is a promising adsorbent for carbon dioxide (CO2) removal due to its large pore volume and high surface area. Solvent-free synthesis of MIL-101(Cr) was employed in this work to offer a green alternative to the current approach of synthesizing MIL-101(Cr) using a hazardous solvent. Characterization techniques including XRD, SEM, and FTIR were employed to confirm the formation of pure MIL-101(Cr) synthesized using a solvent-free method. The thermogravimetric analysis revealed that MIL-101(Cr) shows high thermal stability up to 350 °C. Among the materials synthesized, MIL-101(Cr) at the molar ratio of chromium precursor to terephthalic organic acid of 1:1 possesses the highest surface area and greatest pore volume. Its BET surface area and total pore volume are 1110 m2/g and 0.5 cm3/g, respectively. Correspondingly, its CO2 adsorption capacity at room temperature is the highest (18.8 mmol/g), suggesting it is a superior adsorbent for CO2 removal. The textural properties significantly affect the CO2 adsorption capacity, in which large pore volume and high surface area are favorable for the adsorption mechanism.

Performance Determination of Aluminium Metal Organic Framework in Carbon Dioxide Gas Adsorption

“…It is observed that Al-BDC-1:3 exhibited a better CO2 adsorption performance compared to Al MOFs at 0.045 mmol/g. This result aligns closely with the observations reported in prior literature studies and the SEM morphology in the previous section [16]. The consistent findings suggest that MOFs with a more refined crystal structure exhibit an increased surface area-tovolume ratio.…”

Advances in Metal-Organic Frameworks MIL-101(Cr)

“…The factors affecting the adsorption performance of MIL-101(Cr) include not only the temperature, pressure, and sample forms but also the MIL-101(Cr) crystals structure and the synthesis method. Chong et al [ 73 ] proposed a solvent-free method to synthesize MIL-101(Cr). It was found that the best adsorption performance of MIL-101(Cr) was obtained at a Cr:BDC molar ratio of 1:1, with a BET specific surface area of 1110 m 2 g −1 and an adsorption capacity of 18.8 mmol g −1 for CO 2 .…”

Chromium-based metal-organic framework, MIL-101 (Cr), assisted hydrothermal pretreatment of teff (Eragrostis tef) straw biomass

“…The expected benzene ring bands were observed between 585.55 and 1600 cm −1 including stretching vibrations (C C) at 1399.97 cm −1 and deformation vibrations (C–H) at 1017.62 cm −1 . The moderate band prevailed at 742.97 cm −1 possibly indicating mono substituted benzene and the band at 585.55 cm −1 is ascribed to Cr–O stretching vibration [ 38 ].

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