Dual-function biomimetic carrier based facilitated transport mixed matrix membranes with high stability for efficient CO2/N2 separation

Abstract

Realizing efficient carbon capture by high-performance CO2 separation membrane is significant to mitigate the increasing emissions of greenhouse gas CO2. Inspired by the extraordinary CO2 hydration ability of carbonic anhydrase (CA), a biomimetic MOF (CFA-1) which can mimic the CO2 hydration sites of CA but possesses better stability and the lower price was incorporated into Pebax to fabricated high-performance facilitated transport mixed matrix membranes. The optimal membrane has a CO2 permeability of 869 Barrer with a CO2/N2 ideal selectivity of 88.6 at 1 bar and 30 °C, which is 9.2 times and 2.8 times than the pristine Pebax membrane. Such superior CO2/N2 separation performance (far surpasses 2008 upper bound) is original from the dual-function of CFA-1: (1) provide extra pathways for gas diffusion and affinity sites for preferential CO2 adsorption; (2) facilitate CO2 transport in the membrane by efficiently catalyze CO2 hydration reaction. Furthermore, the Pebax/CFA-1 membranes fabricated can also exhibit excellent stability after being treated under high temperature and harsh pH, which is not available in the Pebax/CA membranes. Overall, such biomimetic dual-function MOFs may pave a new avenue to advance the high-performance CO2 facilitated transport membranes with excellent stability.