Lamellar structured GO-Melamine nanocomposite membranes with varying d-spacing for efficient organic solvent nanofiltration (OSN)

There is a lot of research being done on GO lamellar 2D membranes for separating organic solvents and dyes. These membranes are highly sought-after due to their exceptional characteristics. However, existing challenges include inadequate solvent permeability and limited dye rejection capacity due to swelling of membranes. In this study, we proposed a novel technique that employs low-pressure assisted filtration to fabricate nanocomposite membranes using GO and melamine. Remarkably, these composite membranes exhibited outstanding separation performance for dyes (≥99.06 %) in organic solvents, regardless of their positive or negative charges or when present in mixtures. The optimum GO-M0.02 nanocomposite membrane exhibits impressive organic solvent flux (J), attaining a value as high as 50.8 L/m²h (acetone), which is 6.57 times greater than that of the pure GO membrane. Furthermore, these GO-Melamine nanocomposite membranes showed excellent durability against both common and harsh organic solvents, and the flux of solvents through the GO-M0.02 nanocomposite membrane remained almost unchanged even after being immersed in methanol for up to one week. Additionally, the membrane exhibited consistent solvent flux and rejection rates for methyl green during continuous filtration. These results highlight the exceptional stability and immense potential of GO-melamine nanocomposite membranes for real organic solvent nanofiltration.