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UiO-66 amine functionalized was synthesized by solvothermal method. Post-synthetic modification of UiO-66-NH2with piperazine, a known promoter to enhance the chemisorption rate of CO2uptake, was carried out and analyzed to understand its crystalline structure, morphology and porous structure. Results show that piperazine is an effective agent for enhancing the capacity of absorption of CO2. This porous product exhibits an improved CO2uptake at pressures up to 3000 kPa via physisorption and chemisorption mechanisms. The CH4adsorption and desorption isotherms on UiO-66, UiO-66-NH2and pip-UiO-66-NH2at temperature of 298.15 K and pressures ranging from 0 to 5000 kPa were carried out. IAS theory for a mixture of 0.05 bar CO2, 0.85 bar CH4and 0.1 bar other gas revealed a selectivity factor of 19.09 for CO2/CH4from pip-UiO-66-NH2. Results show that these materials are effective adsorbents for CO2and CH4uptakes.

The solubility of carbonyl sulfide (COS) and also the diffusion coefficients of COS, carbon dioxide, and hydrogen sulfide were experimentally investigated in 1-hexyl-3-methylimidazolium bis(trifluoromethyl) sulfonylimide ([hmim][Tf2N]). The solubility was measured using a static apparatus, and the acid gas diffusivity was obtained by monitoring pressure drop with low initial pressure via the so-called semi-infinite volume method. All experimental absorption trials were carried out in the range of low and medium pressures and temperatures from (313.15 to 353.15) K. Furthermore, all diffusion coefficient experiments were determined at a temperature from (313.15 to 333.15) K and low pressure to some extent to be acceptable in the semi-infinite volume approach. The experimental results were correlated using the Shiflett and Yokozeki versions of the Redlich–Kwong equation of state. In addition, Henry’s law constants and the thermodynamic properties of dissolution at infinite dilution were calculated and discussed.

Sulfur dioxide (SO2) is one of the acidic components found in the flue gas that can harm industrial facilities and the environment. SO2adsorption by metal-organic frameworks (MOFs) is an emerging method to effectively remove SO2in low concentrations from the gas mixtures. In this study, amino-functionalized MIL-53(Al), i.e., NH2-MIL-53(Al), was synthesized through the solvothermal method and examined for SO2adsorption at relatively moderate pressure and temperature (up to 2 bar, 25–80 ℃). According to the results of XRD, FT-IR, TGA, and DSC analysis, NH2-MIL-53(Al) demonstrated appropriate water, acid, and thermal stability. The SO2adsorption capacity of NH2-MIL-53(Al) was 5.21 mmol.g−1at T = 25 °C and P = 0.92 bar, significantly higher than its CO2adsorption capacity under similar conditions, demonstrating its high selectivity for adsorption of SO2relative to CO2. Though the crystal structure of the tested MOF slightly changed after five adsorption/desorption cycles, its SO2adsorption capacity decreased only 6.64%, signifying its proper durability and regenerability under humid and acidic conditions. These features are promising to use NH2-MIL-53(Al) as a suitable adsorbent to selectively remove SO2from flue gas.