Preparation And Characterization Study Of Phase-inversion Ceramic Hollow Fiber Membranes

Membrane separation technology has been rapidly developed and widely applied in new energy, metallurgy industry, environment protection, food processing and petrochemical industry, etc. since its advent. Generally, as an indispensable part of separation membrane, ceramic membrane exhibits better performance, e.g., acid/alkali resistance, high temperature resistance, environmental friendliness, long service life and easy cleaning when compared with polymer membrane. Besides, ceramic hollow fiber membrane has a thinner wall and a higher packing density. This work focus on the preparation of ceramic hollow fiber by adjusting the preparation parameters, and membrane distillation process is carried out using the FAS-modified alumina hollow fiber.In Chapter 1, the related concepts and applications of ceramic hollow fiber membrane are introduced, including preparation and characterization method of ceramic hollow fiber, mechanism and technology of phase inversion extrusion process.In Chapter 2, alumina hollow fiber membranes are prepared by phase inversion method using water as in/out coauglant at different air gaps. The micro structure, pore size distribution, porosity and the permeability of different samples are neasured to find out the effect of air gap. A two-layered structure of inside skin layer and opened finger-like pores layer is fabricated when the air gap goes higher.In Chapter 3, alumina hollow fiber of a two-layered structure with outside skin layer and open-up finger-like pores layer are prepraed by using graphite slurry as internal bore fluid instead of water. Compared with the sample prepared using water as internal coagulant, the two-layered fibers show much better mass transport property because of the open-up finger-like pores and inexistence of sponge layer.In Chapter 4, alumina hollow fiber membranes are applied in sweep gas membrane distillation. Due to the existence of hydroxy, alumina membranes are not suitable for SGMD. Membrane surface is converted from hydrophilic to hydrophobic by grafting with FAS which have a contact angle of 130°. During the distillation test, water flux incerase significantly with the incerase of feed side temperature while decline slightly with the increase of feed side salt concentration. A flux of 13.6 L m 2 h-1 is achieved for the two-layered membrane at the feed side temperature of 80? and salt concentration of 2 wt.%, the flux decline with time and recover after washing the membranes by distilled water. Salt rejection is observed to be over 99.5% during all the tests.In Chapter 5, a summary of this work is present and some suggestions for the related experiment are given.