Graphene Oxide Membranes with Engineered “Pocket Suction” Water Environments for Selective C₁–C₂ Alcohol Dehydration

Graphene oxide (GO), with its tunable subnanometer channels and rich surface chemistry, holds tremendous potential for membrane-based solvent dehydration. However, practical deployment is limited by two key challenges: structural instability caused by aqueous swelling and limited understanding of how pore chemistry governs separation performance. In this work, by integrating microscopic characterization with molecular-level insights, we introduce an interlayer electrostatic anchoring strategy that effectively suppresses swelling by stabilizing the GO lamellar structure while maintaining an optimal water transport channel of ∼1.27 nm. Through further chemical tailoring, we demonstrate that highly oxidized GO pores, particularly those enriched with carboxyl groups, exhibit dramatic water affinity and trigger a cooperative "pocket suction" effect that actively draws water molecules into the membrane interior. This localized driving force accelerates water permeation, while larger alcohol molecules are effectively excluded through a synergistic mechanism of steric hindrance and selective adsorption. Built upon experimentally characterized structural parameters, the resulting realistic, swelling-resistant GO membrane not only survives but thrives in aqueous environments. Remarkably, even at practical membrane thicknesses of several tens of nanometers, it achieves water fluxes exceeding 9.4 kg·m–2·h–1·bar–1 and consistently delivers 100% water purity during both methanol and ethanol dehydration, outperforming state-of-the-art membranes by a wide margin. This work offers molecular-level insights into effective strategies for mitigating swelling in GO membranes and highlights the critical role of pore chemistry, paving the way for next-generation GO membranes with integrated antiswelling stability and exceptional dehydration performance for sustainable bioalcohol production.