Preparation and Characterization of Alumina Membranes on Capillary Supports： Effect of Film-coating on Crack-free Membrane Preparation  

作　　者：朱瑾 范益群 徐南平 

机构地区：[1]State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China

出　　处：《Chinese Journal of Chemical Engineering》2010年第3期377-383,共7页中国化学工程学报（英文版）

基　　金：Supported by the National High Technology Research and Development Program of China （2007AA030303）, the National Basic Research Program of China （2009CB623400） and the National Natural Science Foundation of China （20776067）.

摘　　要：Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support(outer diameter 4 mm,inner diameter 2.5 mm)by a dip-coating method.Scanning electron microscopy(SEM)observation,gas bubble pressure(GBP)method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m -2 ·h -1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support（outer diameter 4 mm,inner diameter 2.5 mm）by a dip-coating method.Scanning electron microscopy（SEM）observation,gas bubble pressure（GBP）method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m ^-2 ·h ^-1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.

关 键 词：CAPILLARY film coating DIP-COATING ceramic membrane 

分 类 号：TQ174.758[化学工程—陶瓷工业] O484.1[化学工程—硅酸盐工业]