TiO₂ Doping of α-Al₂O₃ Hollow Fiber Membranes for Modulating the Sintering Behavior and Surface Property

α-Al₂O₃ ceramic hollow fiber membranes were prepared by a combined phase-inversion and sintering method. Effects of TiO₂ doping on sintering behavior and surface property of hollow fiber membranes were investigated extensively. The results showed that a solid reaction between TiO₂ and α -Al₂O₃ could promote the sintering of α-Al₂O₃ hollow fibers. When the doping TiO₂ content (molar fraction) was 1%-2%, the sintering temperature of hollow fibers could decrease to 1 400 ℃ while the mechanical strength was unchanged. The hydroxyl active sites on the surface of the fibers increased with the doping amount of TiO₂, which was helpful to the growth of the CHA zeolite membrane on the prepared fibers. High-quality CHA zeolite membranes could be prepared on the α-Al₂O₃ hollow fibers doped with a molar fraction of 1%-3% TiO₂, which showed high separation factors above 10 000 for pervaporation dehydration of ethanol/water (9:1, w/w) mixture.