Ionic liquids: a novel material for efficient nanofiltration membranes

Ionic liquids (ILs) have recently emerged as a new membrane material for efficient separation. In this review, current achievements of nanofiltration (NF) membranes modified by ILs are highlighted. ILs, comprising cations and anions, possess excellent tunability of functionalized groups, high polarity, high chargeability, good antimicrobial properties, low vapor pressure, and eco-friendly characteristics, which can enhance the hydrophilicity and chargeability of the NF membrane, provide additional water transport channels and water transport efficiency, as well as improve the ion selectivity, antifouling, and antibacterial properties of the NF membrane for green and sustainable separation process. Meanwhile, the challenges and future research interests toward the interaction behavior between ILs and targeted substance, the regulation of membrane surface interface properties, the separation mechanism, and the inadequacies of s-based NF membranes are discussed.