Dynamic Short Hydrogen-Bonding Network Enhancing Hydrophilicity in Biomimetic Membranes with Artificial Water Channels for Efficient Removal of Dyes and Salts

Abstract

The development of an integrated biomimetic membrane capable of rejecting both dyes and salts in a single step, while sustaining stable water permeation, presents a promising solution for textile wastewater treatment. Herein, we report a novel integrated biomimetic membrane integrating an I-quartet artificial water channel (AWC) with sulfonic acid-modified polyamide (PA-SO3H), which can stably reject both dyes and inorganic salts. The I-quartet channels (2.68 Å), formed via self-assembly of alkyl-ureido-ethyl-imidazole (HC8) molecules, facilitate selective water transport and rejection of both dyes and inorganic salts. Concurrently, the sulfonic acid groups (−SO3H) could grab water molecules, forming dynamic short hydrogen-bonding network (O−H⋅⋅⋅O). These hydrogen bonds not only serve as jumping force, lowering the energy barrier for water transport through the alternating hydrophilic-hydrophobic matrix, but also act as an effective antifouling barrier, significantly reducing membrane fouling. The optimal HC83.0-PA-SO3H membrane exhibits a water permeance of 13.4 L m-2 h-1 MPa-1, approximately 2.7-fold higher than that of the pristine PA membrane, and both high dyes and salts rejection efficiency. Moreover, the membrane sustains stable antifouling characteristics throughout a 19-day endurance test. This innovative membrane design provides a promising solution for the efficient separation of both dyes and inorganic salts in textile wastewater treatment.