Ultra-hydrophobic and mesoporous silica aerogel membranes for efficient separation of surfactant-stabilized water-in-oil emulsion separation

Separation of oil layer/water mixture by the materials with special wettability has made significant progress. However, the effective separation of surfactant-stabilized water-in-oil emulsions by robust and corrosion-resistant materials is urgently desired and remains a worldwide burden. Here, a novel silica aerogel membrane with ultra-hydrophobicity and mesoporous structure is synthesized through a facile one-step sol-gel process and used for efficient surfactant-stabilized water-in-oil emulsion separation. The as-prepared aerogel membranes exhibit superior superhydrophobicity with water contact angle of about 161° even being immersed by corrosive aqueous solutions and oils. More importantly, surfactant-stabilized pure water-in-oil and corrosive water-in-oil emulsions can be effectively separated by the as-prepared aerogel membrane, and the separation efficiency is larger than 99.9%. This silica aerogel-based membrane represents a new route to develop functional materials for removing emulsified water droplets from oil.