Biomimetic nanofiltration membranes: Critical review of materials, structures, and applications to water purification

Emerging contaminants generated due to industrialization have shrunken fresh water bodies. Nanofiltration membranes are relatively efficient at separating contaminants of various sizes and functionalities. Moreover, ease of scale-up, negligible environmental footprint, and energy recovery ability make membrane filtration a future technology for complex water purification. Biomimetic or bioinspired membranes are researched to overcome the permeability-selectivity tradeoff of the existing membranes. Since biological cell membranes can selectively transport various components across membranes via aligned channels, mimicking the architecture can enable the tunable selectivity and removal of various contaminants in wastewater. This comprehensive review examines recent advances in newer materials for biomimetic membranes, their characteristics, and their application for various wastewater treatments. We also discuss various challenges such as difficulty in mimicking the exact cell structure, fouling, and stability of biomimetic materials and present opportunities for further research. We conclude that reproducible and easy processing of biomimetic materials into membranes is required for commercial applications. This review aims at a brief and systematic overview of biomimetic membranes for wastewater treatment and a description of newer materials developed to mimic the biological membranes.