Fig. 1: Fabrication of GO/PG membrane and its nanofiltration performance in water and organic solvents.

a Schematic of the fabrication process for the GO/PG membranes. The right panel is the SEM image of the surface of a GO/PG membrane. Scale bar, 5 µm. The inset is the image of a GO/PG membrane deposited on a nylon substrate. b Permeance of organic solvents through GO/PG membrane as a function of their inverse viscosity. Dotted lines are best linear fits. The physical properties of each organic solvent are listed in Table S1. c MWCO curves of GO/PG membranes in water (black) and methanol (red) containing 10 ppm dye. The MWCO was determined by interpolating from the plot of rejection versus the MW of the dyes obtained from the pressurized nanofiltration experiments. Insets: the diffusion tests for VB molecules diffusing through a GO/PG membrane before (upper) and after (lower) 72 h in water (left) and methanol (right). MWCO curve for (d) pristine GO and (e) pristine PG membrane in water (red) and methanol (black) containing 10 ppm dye solutes. All error bars are standard deviations from at least three different measurements of the independent membrane.