Easy preparation of superoleophobic membranes based on cellulose filter paper and their use for water–oil separation

Owing to the increasing amount of industrial wastewater and ocean pollution, separation of water and oil from their mixtures and emulsions has been an active area in water treatment industry and in academic research. Using cellulose filter paper as the substrate, a porous superoleophobic membrane (OP) was easily prepared by immersing the paper in an acetonitrile solution of toluene diisocyanate and that of N-(2,4-diaminophenyl) maleimide, alternatively and repeatedly, coating the paper with maleimide-containing polyurea (PU). PU coated paper was then functionalized by 2-[(tris(hydroxymethyl)methyl)amino]-1-ethanesulfonic acid through aza-Michael addition. The formation of PU coating and the subsequent functionalization were confirmed by FTIR, NMR and XPS analyses. The produced OP paper was shown to be superoleophobic and had excellent performance for oil–water separation from their mixtures and emulsions. This study provides therefore a novel protocol for preparation of superoleophobic materials, featuring easy operation, low cost, and in particular, versatile applicability to different natural and synthetic materials.