Engineering microporous organic framework membranes for CO2 separations

Abstract

The soaring increase in CO₂ emissions in the atmosphere is drastically changing our global climate and environment. To alleviate this threat, CO₂ separation by membrane technology is evolving as an efficient strategy to control this emission. In the membrane process, membrane materials play a central role. Microporous materials have attracted much attention, particularly for the considerable effort in the recently developed porous organic frameworks (POFs). POFs have a promising potential in membrane applications for CO₂ separation owing to the intrinsic advantages of high porosity and good processability. This review summarizes the latest advances in the development of POF membranes for CO₂ separations from diverse sources. Special attention is focused on effective approaches to engineer the properties of POF membranes in terms of topological design, chemical functionalization and mixed-matrix technique, in order to enhance CO₂ separation performance. The relationship between POF structures and CO₂ permeability (selectivity) is also highlighted. Representative examples of POF membranes for CO₂ separations from flue gas, natural gas or syngas are incorporated. A brief perspective on the future research directions in this rapidly growing field is also given.