超声波强化陶瓷膜分离实验研究

Experimental study on ceramic membrane filtration enhanced by ultrasonic wave

在频率为21kHz功率为20W的超声波辅助作用下采用两种不同孔径的陶瓷膜(0.2μm和50nm)过滤3种不同的原水.实验结果表明:超声波对陶瓷膜滤过程的强化效果因膜污染机理不同而不同.在以沉积过滤(滤饼层)为主的膜过滤过程,超声强化是积极的,声空化、声冲流以及他们引起的浓差极化作用减弱,是导致膜通量提高的主要原因;而以堵塞过滤(膜孔窄化模型)为主的膜滤过程,超声的作用是消极的,超声作用使得更多的溶质进入和吸附于膜孔,从而导致膜通量减少.对地表原水,超声强化积极作用占优,0.2μm和50nm陶瓷膜膜通量分别提高8.2%和5.1%.

An experimental study on the intensifying effect resulted from ceramic membrane filtration enhanced by ultrasonic wave is presented in this paper. Enhanced by ultrasonic wave with frequency of 21 kHz, power of 20 W, three different types of raw water （turbidity water, humus water and lake water） were filtrated by 0.2μm and 50 nm ceramic membranes. The results show that： the effects of ultrasonic wave are different due to the membrane fouling models. To the cake filtration model, ultrasonic effect is positive. The main reason is that acoustic cavitations and ultrasonic streams can decrease the negative effect of concentration polarization and increase membrane filtration flux. However, to the pore narrowing model, the effect is negative because ultrasonic wave can make more solute entering or be absorbed by membrane pores which lead to the decrease of flux. For lake water, ultrasonic intensifying is supreme for its positive effect, and increases the flux of 0.2μm and 50 nm ceramic membrane by 8.2 % and 5.1% respectively.