Abstract
To investigate the effect of ultrasonic irradiation on ultrafiltration (UF) properties, three kinds of solutions : in which a gel layer was easy to form, difficult to form and whose properties were in between, were examined. Ultrasound was irradiated on about 1/8 of the permeation surface of a ceramic membrane. Ultrasonic irradiation affected a gel and a boundary layers. The mass transfer coefficient for UF of ceramic membrane can be correlated to the Sherwood number. The Sherwood number were correlated nearly by Leveque equation without ultrasonic irradiation. But when ultrasound was irradiated, the Sherwood number was larger about by 1.4 times than the one without ultrasonic irradiation. An ultrasonic irradiation had a tendency to decrease the observed rejection slightly by increasing permeation flux whether a gel layer forms on the surface or not.
