The experimental/theoretical study over the effect of using the POP-NH2 nanostructures into the membrane selective layer on the CO2 permeability and selectivity

Abstract

Carbon dioxide (CO2) is a common acidic gas that contributes in some serious environmental, economic, and health problems, such as the global warming, pipeline corrosion, and reducing the efficiency of natural gas combustion. In this study, a functionalized TFC membrane based on the polyethersulfone (PES) support layer and the Pebax selective layer incorporated with the POP-NH2 nanostructures was fabricated to separate the CO2 from CH4 and N2 molecules. The fabricated POP-NH2 nanoparticles and membranes were characterized using different analytical techniques. Modeling calculations were also performed based on the density functional theory (DFT) calculations to understand the interaction between the gases and the POP-NH2 nanostructure. Also, the constant-volume method was utilized to evaluate the performance of the fabricated membranes at various feed pressures and POP-NH2 loading percentages. The functionalized membrane has shown high affinity toward the CO2 molecules and consequently high permeability, compared to the other two gases. The CO2 permeability of 392.2 Barrer and CO2/N2 selectivity of 108.94 (all at 10 bar) were the most prominent results obtained in this study. Also, this high affinity toward the CO2 molecules was also confirmed based on the DFT modeling, as the highest adsorption energy was related to the POP-NH2-CO2 complex.