Facilitated Transport in Hydroxide-Exchange Membranes for Post-Combustion CO2 Separation

• Published in: ChemSusChem Vol. 7; no. 1; pp. 114 - 116
• Main Authors: Xiong, Laj, Gu, Shuang, Jensen, Kurt O., Yan, Yushan S.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.01.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: carbon; Carbon Dioxide - chemistry; Carbon Sequestration; facilitated transport; gas separation; Hydroxides - chemistry; Ion Exchange; Membranes; Membranes, Artificial; Nanoparticles; Organophosphorus Compounds - chemistry; Polymers - chemistry; Sulfones - chemistry; membranes; gas separation; facilitated transport; carbon; ion exchange
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201300286

Hydroxide‐exchange membranes are developed for facilitated transport CO2 in post‐combustion flue‐gas feed. First, a correlation between the basicity of fixed‐site functional groups and CO2‐separation performance is discovered. This relationship is used to identify phosphonium as a promising candidate to achieve high CO2‐separation performance. Consequently, quaternary phosphonium‐based hydroxide‐exchange membranes are demonstrated to have a separation performance that is above the Robeson upper bound. Specifically, a CO2 permeability as high as 1090 Barrer and a CO2/N2 selectivity as high as 275 is achieved. The high performance observed in the membranes can be attributed to the quaternary phosphonium moiety. Star performer: Increasing the basicity of the functional group in hydroxide‐exchange membranes shows an improvement in CO2 separation performance. The newly introduced phosphonium functional group exhibits the best performance of the various functional groups tested.