N-Methyl-2-pyrrolidone or NMP is known to be the best solvent for solution processed GO and RGO. NMP is highly polar, and make a good dispersion with GO. However, if you are working with high concentration and want to filter out the solution you should consider pressure filtration. Hope this helps.
mr Gangopadhyay im looking for a nonpolar solvent because polar solvents lead to coroosion in industries equipments(im trying to produce nonpolar graphene oxide)