Ultrathin graphene oxide-based hollow fiber membranes with brush-like CO₂-philic agent for highly efficient CO₂ capture.

Among the current CO₂ capture technologies, membrane gas separation has many inherent advantages over other conventional techniques. However, fabricating gas separation membranes with both high CO₂ permeance and high CO₂/N₂ selectivity, especially under wet conditions, is a challenge. In this study, sub-20-nm thick, layered graphene oxide (GO)-based hollow fiber membranes with grafted, brush-like CO₂-philic agent alternating between GO layers are prepared by a facile coating process for highly efficient CO₂/N₂ separation under wet conditions. Piperazine, as an effective CO₂-philic agent, is introduced as a carrier-brush into the GO nanochannels with chemical bonding. The membrane exhibits excellent separation performance under simulated flue gas conditions with CO₂ permeance of 1,020 GPU and CO₂/N₂ selectivity as high as 680, demonstrating its potential for CO₂ capture from flue gas. We expect this GO-based membrane structure combined with the facile coating process to facilitate the development of ultrathin GO-based membranes for CO₂ capture.