Cyclic Operation of Forced Flow Electrokinetic Separation for Simultaneous Separation and Concentration of Charged Molecules

Abstract A new cyclic operation of membrane separation in the presence of an electric field is developed. The microporous membrane/filter acts as a barrier between two adjacent solutions (i.e., the solution in the membrane cell and in the permeate). An electric field is applied across the membrane to induce electromigration of charged molecules whose molecular weights are much smaller than the molecular weight cutoff of the membrane used. The charged molecules move freely through pores of the membrane without hindrance. In the presence of an electric field, the concentration of charged molecules in the permeate stream is determined by the electromigration velocity and the permeation flow rate through the membrane. The permeation rate is controlled by the applied pressure drop, and the electro-migration velocity can be controlled by the electric field strength applied. By applying a high electric field and a low pressure drop, the concentration in the permeate stream can be increased, thus resulting in enr...