Prospective applications of nanometer-scale pore size biomimetic and bioinspired membranes

Abstract Biomimetic and bioinspired membranes (BBMs) have garnered significant attention as innovative platforms for membrane-based separations and purification. These membranes typically consist of highly permeable biological or bioinspired pore structures or channels with well-defined pore geometries. The pore structures are embedded in a relatively impermeable synthetic membrane matrix, and the overall membrane demonstrates high performance, functionality, and selectivity originating primarily from the pore properties. The channels utilized have well-controlled and uniform inner pore diameters, leading to a completely uniform pore size distribution, in direct contrast to the wide pore size distribution common in current commercial membranes. Biomimetic membranes thus have the potential to target specific separations that require precise selectivity, particularly in the challenging sub-nanometer to nanometer size ranges. So far, the discussion around BBMs has largely focused on water purification. However, these membranes could provide significant benefits in other potential applications, such as antibiotic separations, homogeneous catalyst retention, organic acid separations, gas separations, organic solvent nanofiltration, and food processing. This review first illustrates the importance of monodisperse pore size distribution to selectivity in nm-scale separations, and then discusses potential applications of BBM membranes. Provided that defect-free biomimetic membranes compatible with the environments used in these applications can be engineered, these membranes may provide a path to move beyond the permeability-selectivity tradeoff that limits the separation properties of current synthetic membranes.