The Effect Of Ultrasound On Microstructure And Separation Performance Of Ceramic Membrane

Filtration flux of membrane usually decreases with time for the concentration polarization and membrane fouling. This has a significant effect on the separation efficiency. So to resolve these problems in the membrane separation process and increase membrane permeation flux is of great significance to process economics and will greatly promote the application of this technology. Based on the review in the work, the ultrasound was introduced into membrane separation process in order to settle this problem. In recent research, the application of ultrasound to membrane separation process focuses on organic membrane and advantages of ultrasound. However, little is studied on application of ultrasound to inorganic membrane and damage of ultrasound to the membrane. This study places emphasizes on the effect of ultrasound on microstructure and filtration performance of tubular ceramic membrane.The effect of ultrasound on microstructure of tubular membrane depends on the intensity of ultrasound. The values of ultrasonic intensity were determined in the beaker, aluminum alloy container and stainless steel membrane module placed in two types of ultrasonic cleaner. It was found that the intensity of ultrasound is different in these containers. The effect of ultrasound of different intensity on ceramic membranes was studied by investigation of pure water flux(PWF), pore size distribution , porosity of membrane and surface topography. It indicated that tubular ceramic membrane was seriously destroyed by ultrasonic intensity about 0.53 W/cm² . And the effect of ultrasound with intensity about 0.27 W/cm² on microstructure of ceramic membrane was also studied. Under this ultrasound irradiation the largest and mean pore size have little changes. But maximum pore size and its distribution change largely, so PWF increases. The effect of ultrasound on ceramic membrane is caused by acoustic streaming and cavitation. It is determined that ultrasound with average intensity of 0.10W/cm² is safe for ceramic membrane.The average CaCO₃ particle size and its distribution have no change after 1 h and 3 h ultrasound irradiation. In the study of ceramic membrane filtrating CaCO₃ particle...