FLUX ENHANCEMENT IN CROSS FLOW MEMBRANE FILTRATION:FOULING AND IT’S MINIMIZATION BY FLOW REVERSAL

University Coal Research Program/Historically Black Colleges and Universities?and Other Minority Institutions

PI: Shamsuddin Ilias

PID  :  74327

来源: CEUR

【 摘 要 】

In crossflow membrane filtration, such reverse osmosis (RO), ultrafiltration (UF) andmicrofiltration (MF), the continuous decline of permeate flux due to concentration polarizationand membrane fouling is a serious problem. To overcome this problem, we introduced theconcept of flow reversal as a method to enhance membrane flux in liquid filtration [1].Conceptually, flow reversal prevents the formation of stable hydrodynamic and concentrationboundary layers at or near the membrane surface. Further, periodic reversal of the flowdirectionof the feed stream at the membrane surface results in prevention and mitigation of membranefouling. Consequently, these advantages enhance the membrane flux significantly.Laboratory scale tests on a hollow fiber ultrafiltration membrane module using bovine serumalbumin (BSA) and Dextran T70 as model solutes show that the permeate flux is significantlyenhanced under flow reversal condition. This effect is dramatic (by an order of magnitude) withincreased feed concentration and operating transmembrane pressure. The essential elements ofthe system include a crossflow hollow fiber membrane module integrated with a threeway valveto direct the feed flow directions. The threeway valve is controlled by a controllertimer forperiodic reversal of flow of feed stream. Another important feature of the system is that withchanging feed flow direction, the permeate flow direction is also changed to maintaincountercurrent feed and permeate flows for enhanced mass transfer driving force (concentrationdifference). In this paper we present the performance data on crossflow ultrafiltration of BSAand Dextran T70 solution under flow reversal and unidirectional flow conditions.References:[1] Ilias, S., Sirena, H, and Talbert, M., “Fluxenhanced crossflow membrane filter,” US Patent