(612b) Real-Time Induced Magnetic Vibration to Reduce Membrane Fouling: Experimental and Modeling Investigation | AIChE

(612b) Real-Time Induced Magnetic Vibration to Reduce Membrane Fouling: Experimental and Modeling Investigation


Tracy, R., The University of Alabama
Esfahani, M., University of Alabama
Mahmoodi, N., The University of Alabama
Membrane fouling continues to be a significant limiting factor, despite the fact that membrane technology has been demonstrated to be one of the most effective ways to treat water. By decreasing membrane permeability and rejection, limiting membrane longevity, and raising process costs due to more frequent washing requirements, fouling decreases the effectiveness of membrane separation. Many articles have been written about chemically altering membranes to lessen fouling. Unfortunately, a number of unfavorable side effects, such decreased flux or selectivity, have been observed as a result of these methods. In this work, we report the implication of real-time induced magnetic vibration as a green method to reduce and/or mitigate membrane fouling without the need to affect the permeability and selectivity of the membrane. Since fouling initiate with the attachment of particles (foulants) on the membrane surface or inside the membrane pores, the implication of magnetic vibration on the membrane surface will prevent or delay the deposition of particles on the membrane surface, resulting in antifouling or lower-intensity fouling. In this method, the membrane excites at higher resonances and takes advantage of the spatial non-uniformity of the resulting mode shapes. In these modes, there will be some regions of the membrane which vibrate out-of-phase with one another, potentially reducing the deposition of particles on the membrane surface (fouling) further by creating instability in the fluid near the membrane surface. Because the amplitude of vibration varies across the membrane surface, the deposition of foulants will also occur unevenly. These uneven patterns of fouling (dis-continued cake layer) may be removed from the membrane more easily during subsequent cleaning. The two-dimensional wave equation was used to identify the effect of frequency on the deposition of particles on the membrane. The experimental investigation confirmed the modeling data where at a higher frequency of 311 Hz the foulant formed a circular pattern near the membrane edges, and at a lower frequency, 190 Hz, the foulants formed a circle pattern in the center of the membrane. A cross-flow filtration system was used to examine the effect of real-time magnetic vibration on the humic acid fouling on the UF polysulfone membrane. The result showed that applying magnetic vibration (28W) reduced the fouling intensity by almost 40 % compared to membranes tested without the magnetic field.