Empowering the moisture removal efficiency of large-scale graphene oxide-based membrane through support layer structure tuning

High performance graphene oxide (GO) based membranes are promising for cost-effective, energy-efficient moisture removal in chemical processing and HVAC systems. However, further improvements to moisture removal rates are limited by the comparably high mass transfer resistance of conventional porous supports, typically needed to overcome the poor mechanical properties of the GO selective layers. To address this bottleneck, we develop asymmetric polyethersulfone supports with significantly higher porosities (up to 95%) compared to commercial supports (45-65%) via a common and scalable non-solvent phase inversion process. By tuning polymer concentration, air gap height during casting, solvent type, and additive concentration, the support morphology was designed to maximize porosity and minimize the top dense layer thickness, while maintaining a low surface roughness ideal for uniform GO coating. After coating with GO, the composite membranes exhibit high water vapor permeances up to 1.35× 10-5 [mol. m-2. s-1. Pa-1] and a water to nitrogen selectivity of 5,900, positioning them among the highest permeances reported to date. This scalable approach to fabricating high-porosity supports opens new avenues for commercial-scale production of GO membranes, potentially transforming energy consumption standards in industrial dehumidification and HVAC systems.