Patent ID: 6149788
Filing Date: 2000-11-21
Classification: B01D,C02F

Abstract:
A method for inhibiting formation of scale in an electrodeionization unit for deionizing water having an anode compartment at one end of the unit, a cathode compartment at the opposite end of the unit, and a plurality of diluting compartments alternating with concentrating compartments positioned between the said anode and cathode compartments, comprising the steps of:passing feed water to be deionized through the diluting compartments to produce a purified water stream;removing scale-forming metallic cations from water or aqueous solution for accepting ions from the feed water;passing said water or an aqueous solution for accepting ions from the feed water through at least one of said concentrating compartments in a direction opposite to that of said feed water;passing water or an aqueous solution through the anode and cathode compartments;applying an electrical voltage between the said anode and the said cathode whereby ions in the feed water migrate to the water or aqueous solution in the concentrating compartments.