Supramolecular polymer-functionalized graphene oxide membranes: a potential approach to sustainable and efficient nanofiltration

Abstract

This study presents a simple supramolecular polymer functionalization strategy to enhance the filtration efficiency, structural stability, and anti-fouling ability of graphene oxide (GO) membranes in nanofiltration. We synthesized water-soluble adenine-grafted poly(ethylene-alt-maleic anhydride) (PE-A) through a one-step method. Owing to its strong affinity, PE-A stably adsorbs to GO and promotes exfoliation into more disordered, isolated nanosheet structures in aqueous environments. Subsequently, a GO/PE-A membrane was fabricated via pressure-assisted filtration on a nylon 6,6 support. The membrane exhibited a uniformly smooth macroscopic morphology, excellent surface wettability, and high structural compatibility. In the nanofiltration assessments, the GO/PE-A membrane significantly outperformed the GO membrane in terms of both water permeability and contaminant removal efficiency. More importantly, in continuous cycles of filtration/washing and anti-fouling tests, the GO/PE-A membrane exhibited excellent structural stability, reusability, and anti-fouling capabilities, demonstrating that the incorporation of PE-A into the GO matrix functionalizes the structural characteristics of GO and effectively improves the overall filtration performance of the membrane. This newly developed supramolecular GO composite membrane holds great potential for water treatment, environmental protection, and advanced separation technologies and may offer a breakthrough solution for current challenges in membrane technology to advance the development of nanofiltration membranes. The supramolecular PE-A polymer-functionalized GO membrane system effectively enhances the structural characteristics and surface physical properties of GO nanosheets to achieve desirable nanofiltration performance.