Fabrication of anti‐fouling thin‐film composite reverse osmosis membrane via constructing heterogeneous wettability surface. Issue 42 (21st June 2021)

• Record Type: Journal Article
• Authors: Chen, Dandan; Gao, Feng; Liu, Tianyu; Kang, Jian; Xu, Ruizhang; Cao, Ya; Xiang, Ming
• Is Part Of: Journal of applied polymer science. Volume 138:Issue 42(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-21
• Subjects: applications -- membranes -- separation techniques -- surfaces and interfaces; Polymers -- Periodicals; Polymerization -- Periodicals; 668.9
• DOI: 10.1002/app.51256
• Languages: English
• ISSNs: 0021-8995

Abstract

Abstract: Anti‐fouling properties are tightly related to the surface properties of reverse osmosis (RO) membranes. In our study, fluorinated polyethyleneimine (FPEI) was synthesized by introducing perfluoroalkyl groups into a hydrophilic polyethyleneimine (PEI) matrix, and the heterogeneous wettability surface with hydrophilic and low‐surface‐energy properties was constructed by grafting FPEI on membrane surface via the carbodiimide‐induced method. Verified by the result analysis of SEM, AFM, and zeta potentials measurements, the fluorinated RO membrane surface presented denser, smoother, and reduced negative charge. The surface free energy of RO membrane surface after grafting FPEI decreased from 45.5 to 38.7 mJ/m 2 . By using bovine serum albumin (BSA), humic acid (HA), and dodecyltrimethyl ammonium bromide (DTAB) as model foulants, the fluorinated RO membrane exhibits optimal fouling resistance and fouling release properties compared to pristine membrane and membrane modified by surface grafting hydrophilic PEI. Especially, the high recovery ratio (99%) and low total flux decline ratio (17.2%) were acquired during the filtration of BSA solution. These results manifested that the construction of a heterogeneous wettability surface can further improve the anti‐fouling properties of RO membranes compared to a pure hydrophilic surface, and the corresponding anti‐fouling mechanism was put forward. Abstract : Anti‐fouling properties of RO membrane are vital in desalination. In this work, a new fluorinated polyethyleneimine (FPEI) monomer was synthesized by a condensation reaction between polyethyleneimine (FPEI) and perfluorooctanoic acid (PFOA). FPEI were grafted onto the commercial membranes by the efficient and mild EDC/NHS method forconstructing a heterogeneous wettability surface of RO membrane, showing optimal anti‐fouling properties to proteins, natural organic matter and positively charged foulants by combing the mechanisms fouling‐resistance and fouling‐release.