Patent ID: 6365023
Filing Date: 2002-04-02
Classification: B01D,B01J,C02F

Abstract:
A water purification process comprising the following steps:(a) providing an electrodeionization module comprising, between a cathode and an anode, at least one ion depletion compartment interposed adjacently between a pair of ion concentration compartments, each compartment containing an ion-exchange medium; (b) passing water through said ion depletion compartment contemporaneously with passing water through said ion concentration compartments; (c) supplying a current between the anode and the cathode in the range of about 1.5Ã—I* and about 15Ã—I*, (i) wherein I*=(QÃ—CÃ—F)/(3600Ã—N), I* being a theoretical minimum current measured in amps, Q being the total water flow rate passing through all ion depletion compartments in said electrodeionization module measured in liters/hour, C being total ion concentration measured in equivalents/liter, F being Faraday's Constant of 96,500 coulombs/equivalent, and N being total number of ion depletion compartments, and (ii) wherein said current is supplied by a power source capable of automatically increasing or decreasing voltage in response to a change in the electrical impedance of the electrodeionization module to maintain constant said current; and (d) recovering water from said ion depletion compartment.