"Like Dissolves Like" Strategy Facilitates Interfacial Polymerization for Facile Synthesis of Highly Permeable Reverse Osmosis Membranes.

Zhou, Shenghua; Xu, Wenjia; Wang, Zhuting; Yao, Keyu; Ji, Chaoyuan; Hou, Tingzheng; He, Yanbing; Guo, Hao · Nano Lett · 2025

basic_science · Level V

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Abstract

Existing reverse osmosis (RO) membranes often feature a polyamide rejection layer fabricated by interfacial polymerization (IP) between <i>m</i>-phenylenediamine (MPD) and trimesoyl chloride. However, polyamide RO membrane formation is limited by the poorly soluble polar MPD in the nonpolar organic solvent (e.g., hexane). Herein, we developed a dual organic solvent system to increase MPD solubility via introducing a polar solvent of dioxane into the hexane as inspired by the classical "like dissolves like" theory and thus promoting the IP reaction efficiency. Consequently, the optimal RO membrane exhibited a superior desalination performance with a rejection of 99.2% for 35,000 ppm of NaCl, simultaneous with a high water permeance of 3.1 L m<sup>-2</sup> h<sup>-1</sup> bar<sup>-1</sup>. Meanwhile, it had a boron rejection of 90.3% that far exceeds commercial RO membranes. These findings demonstrate that a dual organic solvent IP system can offer a facile yet effective strategy for scalable fabrication of high-performance RO membranes.