Perm-selective ultrathin high flux microporous polyaryl nanofilm for molecular separation

Polymeric membranes with high permeance and selectivity performances are anticipated approach for water treatment. Separation membranes with moderate molecular weight cut-offs (MW in between 400 and 700 g mol^-1) are desirable to separate multivalent ions and small molecules from a water stream. This requires polymeric membranes with controlled pore, pore size distribution, surface charge, and thin active layer to maximize membrane performance. Here, a fabrication of the polyaryl nanofilm with thickness down to ∼15 nm synthesized using interfacial polymerization onto ultrafiltration supports is described. Electron microscopy analysis reveals the presence of crumpled surface morphology in polyaryl nanofilm. Polyaryl nanofilm shows high water permeance of ∼110 Lm^-2h^-1 bar^-1. Polyaryl nanofilm presents molecular weight cut-off greater than ∼450 gmol^-1 (molecular marker) with water permeance of ∼84 Lm^-2h^-1 bar^-1. Multivalent salt (K₃[Fe(CN)₆]) has higher rejection (>95%) as compared to the monovalent (∼5%) and divalent salt (∼28%) with the water permeance of ∼81 Lm^-2h^-1 bar^-1.