Facilely Cross-Linking Polybenzimidazole with Polycarboxylic Acids to Improve H2/CO2 Separation Performance

Leiqing Hu; Vinh T Bui; Liang Huang; Rajinder P Singh; Haiqing Lin

doi:10.1021/acsami.0c23098

Facilely Cross-Linking Polybenzimidazole with Polycarboxylic Acids to Improve H₂/CO₂ Separation Performance

ACS Appl Mater Interfaces. 2021 Mar 17;13(10):12521-12530. doi: 10.1021/acsami.0c23098. Epub 2021 Mar 8.

Authors

Leiqing Hu¹, Vinh T Bui¹, Liang Huang¹, Rajinder P Singh², Haiqing Lin¹

Affiliations

¹ Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States.
² Materials Physics and Applications Division, Carbon Capture and Separations for Energy Applications (CaSEA) Labs, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.

PMID: 33683853
DOI: 10.1021/acsami.0c23098

Abstract

Polybenzimidazole (PBI) with a strong size-sieving ability exhibits attractive H₂/CO₂ separation properties for blue H₂ production and CO₂ capture. Herein, we report that PBI can be facilely cross-linked with polycarboxylic acids, oxalic acid (OA), and trans-aconitic acid (TaA) to improve its separation performance. The acids react with the amines on the PBI chains, decreasing free volume and increasing size-sieving ability. The acid doping increases H₂/CO₂ selectivity from 12 to as high as 45 at 35 °C. The acid-doped samples demonstrate stable H₂/CO₂ separation performance when challenged with simulated syngas containing water vapor at 150 °C, which surpasses state-of-the-art polymers and Robeson's upper bound for H₂/CO₂ separation.

Keywords: H2/CO2 separation; carbon capture; cross-linking; membranes; polybenzimidazole; polycarboxylic acid.