Asymmetric porous cordierite ceramic membranes prepared by phase inversion tape casting and their desalination performance

Abstract

Asymmetric porous cordierite ceramic membranes were fabricated by phase inversion tape casting method. It is shown that the membranes consist of a relatively dense skin layer on the top, a sponge layer at the bottom and a finger-like layer in the middle. The membranes have a hierarchical pore structure, where macrovoids (denoted as dozens-micron-sized (DMS) pores) are present in the finger-like layer and micron-sized (MS) pores are located in the skin layer, sponge layer and the wall of macrovoids. After surface silylation by post-grafting with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS), the sample with a starting powder/polyethersulfone (PESf) weight ratio of 9 (M − 4) becomes hydrophobic, with a water contact angle of 150°. At a NaCl concentration of 3.5 wt%, a feed rate of 18L/h and a feed temperature of 80 °C, the hydrophobic M − 4 membrane exhibits a water permeate flux of 22.33 kg/m2h, which is considerably larger than that of the membranes prepared by dry pressing method previously, and a salt rejection of 99.9%. The higher water permeate flux is attributed to the much lower transport resistance of water vapor in the membranes of the present work.