In-situ construction of nanocomposite coating by electrostatic enhanced surface segregation toward antifouling oil-water separation membrane

Abstract

Incorporating hydrophilic nanomaterials onto hydrophobic membrane surfaces has emerged as an effective approach for the preparation of antifouling oil-water separation membranes. In this research, we report an electrostatic enhanced surface segregation method for construction of nanocomposite coating toward antifouling and self-cleaning oil-water separation membranes. Pluronic F127 grafted with carboxyl segments (F127–COOH) is used as segregation agent in the casting solution, while PEI-modified CNT (PEI@CNT) is used as crosslinking agent in the coagulation bath during the non-solvent induced phase separation (NIPS) process, the negatively charged F127–COOH in-situ anchors the positively charged PEI@CNT on the membrane surface via electrostatic interactions, resulting in the formation of nanocomposite coating. The resultant membrane exhibits hydrophilic and underwater superoleophobic property. As a result, the obtained membrane shows high water permeance up to 571.52 L m⁻² h⁻¹ bar⁻¹, with low total permeance decline ratio of 14.18 %, and nearly 100 % permeance recovery ratio during oil-water separation. Furthermore, the optimal membrane also exhibits excellent self-cleaning performance against crude oil. Our work provides a new facile approach for modification of membrane surface with functional nanomaterials.