Engineering Graphene Oxide Laminate Membranes for Enhanced Flux and Boron Treatment with Polyethylenimine (PEI) Polymers.

In this work, we have developed and characterized flux-enhanced graphene oxide laminate (GOL) membranes by increasing interlayer (layer-to-layer) spacing using multibranched polyethylenimine (PEI) polymers with varied molecular weights and by controlling the graphene oxide (GO) oxidation extent. For these assemblies, water flux was demonstrated to increase by as much as ca. 30-fold compared to GO only laminate controls. PEI-embedded GOL membranes also had better methyl orange (MO) rejection performance than GO laminate controls due to the dilution effects (i.e., water is transported through the assembly much faster than MO). Further, boron removal is demonstrated via functionalized PEI with d-glucono-1,5-lactone, containing a high density of boron chelating groups, which can also be recycled/recovered with high efficiency.