Preparation and Characterization of Hydrophobic Porous Yttria-stabilized Zirconia Hollow Fiber for Water Desalination

Porous yttrium-stabilized zirconia(YSZ) hollow fibers with an outer diameter of 1.92 mm,membrane thickness of 0.21 mm were prepared by a combined technique of phase inversion and sintering.The hollow fiber possessed a sandwich structure with long-finger like voids near the inner and outer walls and a thin porous sponge-like layer in the center.The porosity and average pore size of the YSZ hollow fiber were determined to be 54% and 0.56 m,respectively.The surface of the hollow fiber was converted from hydrophilic to hydrophobic by grafting with fluoroalkylsilane(FAS).The as-prepared hydrophobic YSZ hollow fiber exhibited desired water desalination performance operating in the vacuum membrane distillation(VMD).A water flux as high as 48.3 L/(m2 h) was attained with a salt rejection of over 99.7% by exposing the shell side of the fiber to an aqueous solution of 4wt% NaCl at 80℃ and vacuuming the lumen side to a pressure of 4×103 Pa.The membrane distillation performance of the hydrophobic porous YSZ hollow fiber is comparable to the best of polymer membrane,which is promising for water desalination application.