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Author Spotlight: Standardizing the Development of Amine-Based Silica Composites as CO2 Adsorbents for Direct Air Capture
Published on: September 29, 2023
Tertiary-Amine-Functional Poly(arylene ether)s for Acid-Gas Separations
Pablo A Dean1, Yifan Wu2, Sheng Guo2
1Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Abstract:
Competitive sorption enables the emergent phenomenon of enhanced CO2-based selectivities for gas separation membranes when using microporous polymers with primary amines. However, strong secondary forces in these polymers through hydrogen bonding results in low solvent solubility, precluding standard solution processing approaches to form these polymers into membrane films. Herein, we circumvent these manufacturing constraints while maintaining competitive-sorption enhancements by synthesizing eight representative microporous poly(arylene ether)s (PAEs) with tertiary amines. High-pressure H2S, CO2, and CH4 sorption isotherms were collected for these samples to demonstrate enhanced affinity for acid gases relative to the unfunctional control polymer. Although competitive sorption was observed for all samples, improvements were less pronounced than for primary-amine-functional analogs. For H2S-based separations, the benefits of competitive sorption offset decreases in selectivity due to plasticization. This detailed study helps to elucidate the role of tertiary amines for acid gas separations in solution-processable microporous PAEs.
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