A fast and convenient cellulose hydrogel-coated colander for high-efficiency oil-water separation

A cellulose hydrogel was successfully prepared in alkali/urea solution using a freezing/melting method and was coated on nylon mesh. The as-prepared mesh was superhydrophilic in air with a water contact angle of 0 degrees and superoleophobic under water with an oil contact angle above 150 degrees. The hydrophobicity was well maintained in various aqueous phases, which reflects its stability under severe conditions. The mesh was effective in oil-water separation because water quickly permeated through the mesh while oil was obstructed. Separation can be efficiently performed without auxiliary power. A colander was also fabricated with the mesh that can be used to scoop waste oil floating on water.