Robust superhydrophobic/superoleophilic filter paper for effective separation of oil/water mixtures and surfactant-stabilized water-in-oil emulsion

Abstract

Recently, the super-wetting materials for oil/water separation have attracted great attention. Developing a low-cost and high-efficient filter material that is challenging to separate oil/water mixtures and stable water/oil emulsions efficiently. In this paper, Nano titanium dioxide is hydrophobically modified with γ-aminopropyltriethoxysilane (KH550), and then added with polydimethylsiloxane to make stable superhydrophobic coating. A coated filter paper is obtained by roll coating. The water contact angle of the coated filter paper reaches more than 152°, and the oil droplets are quickly absorbed. The superhydrophobic/superoleophilic filter paper has the advantages of environmental protection, simple operation, low-cost, and can be used in continuous industrial production. The superhydrophobic filter paper is used for the separation of various immiscible oil-water mixtures, the separation efficiencies are more than 99.5%. In addition, the superhydrophobic filter paper can effectively separate various surfactant-stabilized water/oil emulsions. After 10 cycles, the separation effect is still satisfactory. Especially when the proportion of water in water/oil emulsion is as high as 20%, the separation efficiency can still be higher than 97.5%. The results show that the superhydrophobic filter paper has good oil-water separation ability, and has broad prospects in industrial applications.