LAUSR

Abstract The excellent properties of superwetting materials make it possible to deal with complex interfacial problems such as water-in-oil emulsions separation. However, it remains a challenge to develop an efficient and facile method to eliminate the adverse effects of trace water in transformer oil. In this work, a robust copper oxide-based superhydrophobic microfiltration membrane was prepared by a simple spray-coating method for moisture-proof treatment of trace water in transformer oil. For the first time, the emulsion separation was carried out by the combine of inorganic aluminum phosphate and metal oxide. After oxidation and rapid surface modification by octadecanethiol, the fabricated membrane become extremely repel water and can separate various of transformer oils with the efficiency higher than 99.995%, and the efficiency can remain stable even after 20 separation cycles. TGA test reveal that the collected transformer oils possess same thermal stability as original transformer oil. Moreover, after 50 abrasion cycles, only a simple re-modification process is required to restore the separation efficiency of the membrane. Besides, the membrane also displayed prominent chemical resistant to acid, alkali, and salt solutions. This work provides a new method for purifying water-in-transformer oils emulsions with high efficiency and low energy consumption, which advances the moisture-proof treatment for transformer oil.