Development of large-scale laminar-structure nanofiltration membranes for high dye rejection and enhanced robustness: Utilizing potassium ion-crosslinked graphene oxide and polyethyleneimine surface coating

Abstract

Laminar graphene oxide (GO) membranes are at the forefront of groundbreaking research as a prospective advanced solution for nanofiltration. Both physical and computational experiments have showcased the exceptional efficacy of these GO membranes. However, scalability and robustness issues still remain significant hurdles for the practical implementation of GO membranes. In this study, to address these issues concurrently, we employed tape-casting of GO hydrogel induced by potassium ion crosslinking alongside polyethyleneimine crosslinking between the tape-casted laminar GO layers and the porous support layer. Through this approach, we successfully crafted a scalable laminar GO membrane encompassing an area of 900cm², characterized by good uniformity. The GO membranes achieved excellent rejection efficiencies of 99.22%, 99.42%, and 99.27% for methylene blue, methyl orange, and rhodamine B, respectively, with 0.77 LMH/bar of pure water permeability. Furthermore, the GO membranes demonstrated enhanced stability, validated by both long-term operation and testing under harsh conditions.