Laminated superwetting aerogel/membrane composite with large pore sizes for efficient separation of surfactant-stabilized water-in-oil emulsions

Abstract

Although superwetting filtration membranes have been widely used, they suffer from the disadvantages of low flux and membrane fouling caused by the nanoscale pore size. Herein, a laminated cellulose aerogel/membrane composite with large pore size is fabricated via combining facile freeze-drying and hydrophobic modification using cellulose fibers as building blocks. An ultrathin silanization coating layer on cellulose fibers surface is constructed via directly coupling alkoxysilane and endows the composite with excellent superhydrophobicity (161°) and superoleophilicity (0°). Upon contact with a water-in-oil emulsion, the aerogel layer causes the micrometer-sized water droplets to coalesce. The coalesced water droplets are then repelled by the membrane layer with large pore size, achieving ultrafast gravity-driven separation with high separation efficiency (99.5%) and separation flux (12890 L m−2 h−1). Moreover, the composite exhibits ease to cycle and good usability. The outstanding performance of composite highlights its potential applications in the field of oil related industry.