Evolution of functional nanochannel membranes

Small molecules and ions pass through molecular separation membranes with channels at the nanometer scale. These nanochannel membranes are playing an increasingly important role in recycling and recovering clean water, as well as in the purification and separation of molecules in chemical, environmental, and pharmaceutical fields in addition to other industries. However, it is still a challenge to maintain the ideal properties of well-defined, internal nanoscale structures of nanochannel membranes during separation, which inspires the development of next-generation all-in-one functional nanochannel membranes (FNMs). FNMs are intelligent nanochannel membranes that integrate selective separation and environmental self-adaptive functions by external stimuli such as light, pH, temperature, electricity, or enzymes. This review presents recent advances of FNMs for high-performance separation and/or chemical synthesis. It highlights nanostructure design strategies to introduce these functions into molecular sieve membranes and their versatile applications. The potential challenges and opportunities of FNMs are also identified. Overall, this critical review summarizes the material-structure-performance relationships between functional materials, the nanostructure of FNMs, their applications in various industries, and their impacts on humans and our environment.