Simulation and Experiment of CO₂ Philicity and Separation in Carbonate-Rich Polymers

Abstract

Functional polymers containing CO 2 -philic groups are of great interest for membrane CO 2 /gas separation for carbon capture. This work, for the first time, systematically elucidates the effect of carbonate groups on CO 2 /gas solubility selectivity and permselectivity using an integrated simulation and experimental approach in two carbonate-rich polymers: poly(ethylene carbonate) (PEC) and poly(propylene carbonate) (PPC). Both polymers are amorphous and rubbery at 35 °C, and they are thoroughly characterized for physical properties and CO 2 /gas separation properties. PEC exhibits a CO 2 /C 2 H 6 solubility selectivity of 24 at 35 °C, much higher than that of poly(ethylene oxide) (2.8), one of the leading membrane materials for CO 2 /gas separation. The binding energy between gas molecules and polymer analogue was calculated using density functional theory (DFT), and the results are consistent with the experimental sorption data. Both PEC and PPC show CO 2 / CH 4 permselectivity of ≈53 at 35 °C, the highest reported for rubbery polymers. PEC also exhibits a CO 2 /N 2 permselectivity of 74, one of the best reported in the literature. Although polar carbonate groups may lower gas permeability, they can be incorporated into polymer architectures to improve CO 2 /gas selectivity.

Machine Learning-Guided Discovery of Polymer Membranes for CO2 Separation

“…Application of this combined ML-GA framework results in the discovery of more than 20 new polymers that are above both the CO 2 /N 2 and CO 2 /O 2 Robeson upper bounds, many of which contain aromatic functional groups along with oxygen-and nitrogen-motifs, aligning with experimental observations that show imines and polyethers as promising polymer membranes for CO 2 separation (32)(33)(34)(35)(36).…”

Polymer Sorbent Design for the Direct Air Capture of CO2

“…One potential method, among many others, to explore these phenomena is through computational modeling and simulations. Currently, computational studies have been thoroughly leveraged to explore many factors at a system-design level including process optimization, fluid dynamics, and screening of sorbents for improving adsorption capacities. − Moreover, there has been significant work in investigating molecular phenomena through both density functional theory studies and molecular level simulations to provide fundamental insight into interactions between sorbents and CO 2 molecules. − Moving forward, similar approaches can be taken to comprehensively investigate the governing physics in these reactive systems.…”

Retarded O2 transport in Co2+-coordinated supramolecular polymer networks for membrane CO2/O2 separations

“…29 Pure-gas sorption in the SPNs (∼2 g) was determined using a dual-volume and dual-transducer apparatus based on the pressure-decay method at 35 °C and three pressures (∼4.5, ∼7.9, and ∼11.4 bar). 30…”