Super-wetting, photoactive TiO2 coating on amino-silane modified PAN nanofiber membranes for high efficient oil-water emulsion separation application

A super-wetting, photoactive nanofiber (NF) is prepared by coating PAN-Si NF precursor with TiO2 NPs and self-made photoactive TiO2 gel for the first time. PAN-Si NF is obtained by amination reaction with (3-Aminopropyl)triethoxysilane. A rough TiO2 layer with a full surface coverage is formed through the condensation reaction between TiOH and SiOH group and self-condensation among TiOH groups. The surface Ti content of the prepared NF reaches 17.18% (atom ratio), which is almost the highest report for the TiO2 modified polymers till now. Furthermore, the separations of several different types of oil emulsions with or without surfactant are tested. An excellent antifouling property is found in the separation of petroleum ether emulsion. A high flux about 200,000 Lm(-2) h(-1) bar(-1), is found in the separation of pump oil (1%) emulsion without surfactant. Moreover, it is found that both the oil drop size and surfactant play an important role in the separation of pump oil emulsion. However, a serious fouling phenomenon is observed in the separation of soybean oil emulsion. The reason is due to the smaller oil drops size (less than 1 mu m) in its emulsion. But the flux can be fully recovered after UV-irradiation treatment. Finally, the relationship between the separation performance of membrane and the oil drop size is built for the first time. A trade-off line is developed to compare the performance of membranes reported in the literature, and our membrane shows a good comprehensive performance.