Smart Two‐Dimensional Membranes for Molecular Separations

Abstract

Membrane-based separation technologies are gaining prominence in energy-efficient separation processes. Smart membranes, which change their physical or chemical characteristics in response to environmental stimuli, are attractive membrane candidates. This review summarizes the recent development and applications of smart membranes based on two-dimensional (2D) materials, mainly focusing on their design, fabrication, and applications in molecular separations. Furthermore, stimuli for triggering smart 2D membranes are classified and explained. Finally, we propose areas for improvement and further development for future studies, such as the issues of complicated fabrication, long term stability in real operating conditions, and responding to different environmental stimuli at the same time.

Covalent organic frameworks for CO2 capture: from laboratory curiosity to industry implementation

“…Unlike 2D graphene or graphene oxide membranes, pure COF membranes have much shorter mass transfer paths and thus have the paramount potential for ultimate separation. 156 However, in light of the similar size of 0.33, 0.364, and 0.38 nm for CO 2 , N 2 , and CH 4 , respectively, most COFs with large pore sizes are inadaptable and difficult to be used in CO 2 capture directly, and the separation performance is insufficient to break the upper bonds. 157 Therefore, forming MMMs is an optional way to improve CO 2 capture performance.…”

Smart dynamic hybrid membranes with self-cleaning capability

“…Over the past decade, several advanced membranes have been suggested, aimed at improvement of some functionalities such as tuneable permeability, enhanced selectivity and fouling resistance 14 . Drawing on inspiration from stimuli-responsive cell channels 15 , smart gating membranes have been proposed for water treatment 16 with capability for self-modulation of their pore size and/or surface properties by using gradients in temperature 17 , light 18 , pH 19 , magnetic 20 or electric fields 21 , and specific ions or molecules 22 , 23 . Within the hybrid membrane approach, smart gating membranes have been prepared based on coupling of stimuli-responsive materials with traditional porous membranes 24 or by using surface functionalization 25 .…”