Unveiling the Growth of Polyamide Nanofilms at Water/Organic Free Interfaces: Toward Enhanced Water/Salt Selectivity
Shenghua Zhou, Li Long, Zhe Yang, Sik Lui So, Bowen Gan, Hao Guo, Shien‐Ping Feng, Chuyang Y. Tang
Abstract
-phenylenediamine and dangling acyl chloride groups within the formed polyamide film. This continued growth of the polyamide nanofilm led to a simultaneous increase in its crosslinking degree (from 50.1 to 94.3%) and the healing of nanosized defects, resulting in a greatly enhanced rejection of 99.2% for NaCl without sacrificing water permeance. Using humic acid as a molecular probe for sealing membrane defects, the relative contributions of the increased crosslinking and reduced defects toward better membrane selectivity were resolved, which supports our conceptual model involving both enhanced size exclusion and healed defects. The fundamental insights into the growth mechanisms and the structure-property relationship of the polyamide nanofilm provide crucial guidance for the further development and optimization of high-performance RO membranes.