Fabrication of Hollow Fiber Supported TiO2 Ultrafiltration Membranes via Ultrasound-assisted Sol-Gel Method

Ti O2 membranes have been applied in ultrafiltration （UF） separation due to their strong hydrophilicity and good thermochemical stability,but most of them are tubular membranes with low permeation flux and time-consuming preparation.To improve the flux and save the preparation time of Ti O2 membrane,hollow fiber supported Ti O2 UF membranes were prepared via ultrasound-assisted Sol-Gel method by using tetrabutyl titanate as precursor.Effects of acid/titanium molar ratio,ultrasound time and calcination temperature on Ti O2 sols and UF performance of membranes were investigated extensively.The results showed that when the acid/titanium ratio was0.25,the obtained Ti O2 sol showed an average particle size of 3252 nm,which would be reduced to 1817 nm after ultrasonic treatment for 30 s.Coating with the above Ti O2 sol,defect-free Ti O2 UF membrane with average thickness of 1μm can be prepared on hollow fiber support by calcining at 350℃twice.The pure water flux of the obtained membrane was 145 L·m–2·h–1·bar–1,and the dextran molecular weight at 90%rejection of membrane was2586 Da with corresponding average pore size of 2.5 nm.