Liquid-phase water isotope separation using graphene-oxide membranes

We report pressure-driven liquid-phase isotope separation (dead-end filtration) to enrich D and 18O in natural water using graphene oxide (G-O) UV-reduced (UV-rG-O) membranes. The diffusivity (molecular diffusion adsorption separation) was found be responsible for separation. Adsorption is the dominant mechanism improvements enrichment via increased G-O loading that leads number of sites (epoxy hydroxyl groups on G-O), higher degrees reduction result narrowing nanochannels which decreases portion molecules experiencing molecular diffusion. best performing membrane “UV-rG-O” made by exposing a 24 h UV irradiation from one side, showing 0.5% D/H 0.08% 18O/16O single-stage experiment, without contribution vapor pressure effect. This work improves understanding mechanisms graphene-based enriched water.