CO2-switchable membranes: structures, functions, and separation applications in aqueous medium

Abstract

Membrane separation has become one of the key separation technologies, which play vital roles in food and medicine production, chemical industries, water treatment, etc. Inspired by natural cell membranes with stimuli-responsive channels, artificial stimuli-switchable membranes have drawn growing attention in various fields. Among them, CO₂-switchable membranes are highly appealing because of the great features of CO₂ as being abundant, nontoxic, environment-friendly, free of contamination in use and good reversibility. In this Highlight article, we review the recent development of CO₂-switchable membranes in aqueous medium in separation fields, showcasing applications such as controlled release, oil–water separation, self-cleaning of membranes and size-/charge-based separation. We present the working principles and challenges of CO₂-switchable membranes, and also give our opinion on possible opportunities for future research directions and applications.