Selective Adsorption Of CO₂on MOFs（Al）

As the world’s population increases, the global energy shortage becomes a vital problem. Because fossil fuels are currently the main energy sources, their burning releases a great deal of greenhouse gases like CO2, leading to global warming eventually. Nowdays, metal-organic materials (MOFs) attract great attention in the field of gas adsorption and separation due to their excellent properties, such as lager surface area, chemical modifiability, and high porosity etc. This MSc theis mainly consists of the following aspects:1. NH2-MIL-101(Al) was hydrothermally synthesized, based on the recipe from the reference. The single-component adsorption isotherms of CO2, CH4and N2on NH2-MIL-101(Al) were systematically investigated by means of a volumetric method at298,310and323K. The Langmuir model can appropriately describe the measured adsorption isotherm data. Based on the difference in adsorption strength among the adsorptives investigated on the adsorbent, breakthrough-column technique was used to study the separation performance of CO2/CH4and CO2/N2mixtures. The results show that NH2-MIL-101(Al) can effectively separate these mixtures. The ideal adsorbed solution theory (IAST) was applied to predict the binary adsorption by single-component adsorption properties, indicating that the IAST predictions are in good agreement with the experimental observatins, i.e., with the increase pressure at a constant temperature, the adsorption selectivity for CO2increases while the selecitivity for CO2decreases with increasing temperature at a given pressure.2. A series of MIL-53(Al) with different amino loadings were synthesized by tuning the mole ratio of amino terephthalic acid to terephthalic acid. The characterization results show that the sample specific surface area, pore volume and thermal stability of the synthesized samples were decreased with increasing the amino loading in the samples. The single-component adsorption isotherms of CO2, CH4and N2on MIL-53(Al) with different amino loadings at298,310, and323K were systematically investigated using a volumetric method. The results show that the adsorption selectivity for CO2increases with increasing the amino loading in the adsorbent. In addition, the separation properties of CO2/CH4and CO2/N2mixtures on MIL-53(Al) and NH2-MIL-53(Al) were systematically investigated by breakthrough-column technique. The results show both of them can effectively separate these mixtures. There is remarkable rolling up phenomenon because of large difference in adsorption strength bewteen adsorbates.