Ideal Adsorbed Solution Theory (IAST) is a predictive model that does not require any mixture data. In gas purification and separation processes, IAST is used to predict multicomponent adsorption equilibrium and selectivity based solely on experimental single-component adsorption isotherms. In this work, the mixed gas adsorption isotherms were predicted using IAST calculations with the Python package (pyIAST). The experimental CO₂ and CH₄ single-component adsorption isotherms of Mg-gallate were first fitted to isotherm models in which the experimental data best fit the Langmuir model. The presence of CH₄ in the gas mixture contributed to a lower predicted amount of adsorbed CO₂ due to the competitive adsorption among the different components. Nevertheless, CO₂ adsorption was more favorable and resulted in a higher predicted adsorbed amount than CH₄. Mg-gallate showed a stronger affinity for CO₂ molecules and hence contributed to a higher CO₂ adsorption capacity even with the coexistence of a CO₂/CH₄ mixture. Very high IAST selectivity values for CO₂/CH₄ were obtained which increased as the gas phase mole fraction of CO₂ approached unity. Therefore, IAST calculations suggest that Mg-gallate can act as a potential adsorbent for the separation of CO₂/CH₄ mixed gas.

The development of Faujasite (FAU) zeolite membranes has been a subject of interest for various application due to the uniform pore’s characteristic, excellent thermal, and chemical stability as well as catalytic and ion-exchange properties of FAU zeolite membranes. However, the synthesis of FAU zeolite membranes with minimum defects is still challenging as there are multiple variables in the synthesis process which need to be controlled. This review started with an overview on zeolites, zeolite membranes, and their applications. Then, various methods used for the preparation of FAU zeolite membrane are discussed. Subsequently, the variation of synthesis techniques and parameters for obtaining high quality of FAU zeolite membrane are reviewed. Then, the parameters affecting the formation of FAU zeolite membrane are highlighted.

CO₂ separation from CH₄ by using mixed matrix membranes has received great attention due to its higher separation performance compared to neat polymeric membrane. However, Robeson’s trade-off between permeability and selectivity still remains a major challenge for mixed matrix membrane in CO₂/CH₄ separation. In this work, we report the preparation, characterization and CO₂/CH₄ gas separation properties of mixed matrix membranes containing 6FDA-durene polyimide and ZIF-8 particles functionalized with different types of amine groups. The purpose of introducing amino-functional groups into the filler is to improve the interaction between the filler and polymer, thus enhancing the CO₂ /CH₄ separation properties. ZIF-8 were functionalized with three differents amino-functional group including 3-(Trimethoxysilyl)propylamine (APTMS), N-[3-(Dimethoxymethylsilyl)propyl ethylenediamine (AAPTMS) and N¹-(3-Trimethoxysilylpropyl) diethylenetriamine (AEPTMS). The structural and morphology properties of the resultant membranes were characterized by using different analytical tools. Subsequently, the permeability of CO₂ and CH₄ gases over the resultant membranes were measured. The results showed that the membrane containing 0.5 wt% AAPTMS-functionalized ZIF-8 in 6FDA- durene polymer matrix displayed highest CO₂ permeability of 825 Barrer and CO₂/CH₄ ideal selectivity of 26.2, which successfully lies on Robeson upper bound limit.

Within three decades of fundamental findings in research on metal–organic frameworks (MOFs), a new family of hybrid materials known as gallate-based MOFs, consisting of metal salt and gallic acid, have been of great interest. Due to the fact that gallic acid is acknowledged to display a range of bioactivities, gallate-based MOFs have been initially expended in biomedical applications. Recently, gallate-based MOFs have been gradually acting as new alternative materials in chemical industrial applications, in which they were first reported for the adsorptive separation of light hydrocarbon separations. However, to date, none of them have been related to CO₂/CH₄ separation. These porous materials have a bright future and can be kept in development for variety of applications in order to be applied in real industrial practices. Therefore, this circumstance creates a new opportunity to concentrate more on studies in CO₂/CH₄ applications by using porous material gallate-based MOFs. This review includes the description of recent gallate-based MOFs that presented remarkable properties in biomedical areas and gas adsorption and separation, as well as their future potential application.

CO₂ separation from raw natural gas can be achieved through the use of the promising membrane-based technology. Polymeric membranes are a known method for separating CO₂ but suffer from trade-offs between its permeability and selectivity. Therefore, through the use of mixed matrix membranes (MMMs) which utilizes inorganic or hybrid fillers such as metal-organic frameworks (MOFs) in polymeric matrix, the permeability and selectivity trade-off can be overcome and possibly surpass the Robeson Upper Bounds. In this study, various types of MOFs are explored in terms of its structure and properties such as thermal and chemical stability. Next, the use of amine and non-amine functionalized MOFs in MMMs development are compared in order to investigate the effects of amine functionalization on the membrane gas separation performance for flat sheet and hollow fiber configurations as reported in the literature. Moreover, the gas transport properties and various challenges faced by hollow fiber mixed matrix membranes (HFMMMs) are discussed. In addition, the utilization of amine functionalization MOF for mitigating the challenges faced is included. Finally, the future directions of amine-functionalized MOF HFMMMs are discussed for the fields of CO₂ separation.