Tweak in Puzzle: Tailoring Membrane Chemistry and Structure toward Targeted Removal of Organic Micropollutants for Water Reuse

Abstract

Membrane-based water reuse through reverse osmosis (RO) and nanofiltration (NF) faces a critical challenge from organic micropollutants (OMPs). Conventional polyamide RO and NF membranes often lack adequate selectivity to achieve sufficient removal of toxic and harmful OMPs in water. Tailoring membrane chemistry and structure to allow highly selective removal of OMPs has risen as an important topic in membrane-based water reuse. However, a critical literature gap remains to be addressed: how to design membranes for more selective removal of OMPs. In this review, we critically analyzed the roles of membrane chemistry and structure on the removal of OMPs and highlighted opportunities and strategies toward more selective removal of OMPs in the context of water reuse. Specifically, we statistically analyzed rejection of OMPs by conventional polyamide membranes to illustrate their drawbacks on OMPs removal, followed by a discussion on the underlying fundamental mechanisms. Corresponding strategies to tailor membrane properties for improving membrane selectivity against OMPs, including surface modification, nanoarchitecture construction, and deployment of alternative membrane materials, were systematically assessed in terms of water permeance, OMPs rejection, and water-OMPs selectivity. In the end, we discussed the potential and challenges of various strategies for scale-up in real applications.