Scalable Graphene Oxide Hollow Fiber Membranes for Dye Desalination Enabled by Multi‐Purpose Polyamine Functionalization

Abstract 2D nanosheets such as graphene oxide (GO) can be stacked to construct membranes with fine‐tuned nanochannels to achieve molecular sieving ability. These membranes are often thin to achieve high water permeance, but their fabrication with consistent nanostructures on a large scale presents an enormous challenge. Herein, GO‐based hollow fiber membranes (HFMs) are developed for dye desalination by synergistically combining chemical etching to form in‐plane nanopores (10–30 nm) to increase water permeance and polyamine functionalization to improve underwater stability and enable facile large‐scale production using existing membrane manufacturing processes. HFM modules with areas of 88 cm 2 and GO layer thicknesses of ≈500 nm are fabricated, and they exhibited a stable dye water permeance of 75 L m −2 h −1 bar −1 , rejection of >99.5% for Direct red and Congo red, and Na 2 SO 4 /dye separation factor of 300–500, superior to state‐of‐the‐art commercial membranes. The versatility of this approach is also demonstrated using different short polyamines and porous substrates. This study reveals a scalable way of designing 2D materials into high‐performance robust membranes for practical applications.