Innovative construction of nano-wrinkled polyamide membranes using covalent organic framework nanoflowers for efficient desalination and antibiotic removal

Abstract

In recent years, the scientific community has identified the intriguing potential of polyamide (PA) nanofiltration (NF) membranes with nano-wrinkled structures, promising to transcend the longstanding permeability-selectivity trade-off inherent in conventional membranes. The present study advances this frontier by masterfully employing covalent organic framework (COF) nanoflowers, meticulously constructed on substrate surfaces using a sophisticated layer-by-layer self-assembly technique. This innovation mediates the interfacial polymerization (IP) process, integral to PA NF membrane fabrication. Through rigorous analysis employing scanning electron microscopy and atomic force microscopy, the derived PA membrane was found to exhibit a distinctive nano-wrinkled morphology. Remarkably, this novel structure yielded a pure water permeance nearly threefold that of control membranes with conventional nodular PA layers. This enhancement is attributed to a synergistic combination of factors that includes increased surface hydrophilicity, greater surface area, thinner PA layer, and an optimized water transport pathway. Furthermore, this membrane demonstrated an impressive 98.7 % Na2SO4 rejection rate, greater than 96.4 % rejections for four critical antibiotics, and commendable stability in flux with superior anti-fouling characteristics. These groundbreaking insights open new avenues for the development of high-performance nano-wrinkled PA membranes, with far-reaching implications for various environmental applications.