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Universal Rapid Demulsification by Vacuum Suction Using Superamphiphilic and Underliquid Superamphiphobic
Pan Wu1, Qiuxian Luo1, Xingyang Zhang1
1Low-Carbon Technology and Chemical Reaction Engineering Laboratory, School of Chemical Engineering, Sichuan University, Chengdu 610065 P. R. China.
Abstract:
A process for universal rapid demulsification by vacuum suction using an as-prepared superamphiphilic and underliquid superamphiphobic polyurethane (PU)/diatomite composite has been developed and is used to demulsify kerosene-in-water and water-in-kerosene emulsions with and without a surfactant. The results show that the demulsification rate of all the emulsions exceeds 98.5% in long-term operation, with a stable demulsification speed exceeding 0.303 L/m2 min. When a superhydrophobic channel for separation is added, the oil/water separation efficiency exceeds 99.0%, and the final products are qualified oil and water. This attractive universal demulsification capability of PU/diatomite originates from its underliquid superamphiphobicity, which attracts a continuous phase to form a stable liquid film and thus repels dispersed phase droplets, which have a similar interaction with the surface but are much less abundant. The vacuum forces emulsion droplets into the microstructure of the PU/diatomite cake, where they are compressed, coalesce, and finally demulsified. This observed mechanism suggests a promising strategy to avoid the negative effects of oil fouling in demulsification and achieve large-scale universal continuous rapid demulsification.
