Membrane separation is now widely applied for such purposes as biotechnology, clarifying fruit juices, and waste water treatment, but is limited by the presence of concentration polarization and membrane fouling. De, Sunando DasGupta (both Indian Institute of Technology, Khoragpur), and Biswajit Sarkar (chemical technology, U. of Delhi) explain a technique for reducing those problems by applying an external direct current electric field. With appropriate polarity, they say, charged solutes migrate away from the membrane surface due to electrophoresis, thus reducing the concentration polarization and deposition thickness and enhancing the permeate flux. They cover clarifying citrus fruit juice, separating and fractionating protein solution, and electric field assisted micellular enhanced ultrafiltration. Annotation ©2010 Book News, Inc., Portland, OR (booknews.com)
