High flux composite membranes based on glass/cellulose fibers for efficient oil-water emulsion separation

Abstract

It is a challenge to develop an oil-water separation membrane that simultaneously meets the requirements of environmentally-friendly, low-cost, high flux, high wet strength, and excellent separation efficiency. Herein, composite membranes based on glass and cellulose fibers were prepared by a series of steps including cellulose fiber skeleton construction, maleic anhydride (MA) modification, and plasma treatment. The micro-sized beaten cellulose fibers and nano-sized bacterial nanocellulose (BC) are interlaced with each other during the layer upon layer deposition via vacuum filtration, thus effectively fixing the glass fibers. Combined with MA crosslinking, the wet strength of the composite membrane is greatly increased to 6.55 N·m/g. Besides, the underwater superoleophobicity of the composite membrane (UOCA＞150°) was realized by constructing the micro- and nano-scale roughness through plasma treatment. When used for oil-water emulsion separation, an ultrahigh flux up to 12, 070 L/m2·h with the separation efficiency of ≥ 98.1% were achieved for the composite membranes solely under the driving of gravity. Micro- and nano-scale fibers are used to synergistically increase strength, and the hierarchical roughness is generated as an inherent property of the membrane. The unique structure resulting underwater superoleophobic composite membrane is of practical interest for oily wastewater treatment.