Low scale potential water treatment

Abstract

An electrochemical treating device having low scale potential is disclosed. The device has a variety of configurations directed to the layering of the anionic exchange and cationic exchange. The treatment device can also comprise unevenly sized ion exchange resin beads and/or have at least one compartment that provides a dominating resistance that results in a uniform current distribution throughout the apparatus.

1 . An electrodeionization apparatus comprising:
 a depleting compartment; and   a first concentrating compartment in ionic communication with the depleting compartment, and defined at least partially by an anion selective membrane and a cation selective membrane, the first concentrating compartment containing at least partially a first zone comprising substantially of cation exchange media that is substantially separated from the anion selective membrane by a second zone comprising substantially of anion exchange media,   wherein the first concentrating compartment comprises electrochemically inert media in an amount that adjusts the effective current resistance of the first concentrating compartment to a desired effective resistance.   
     
     
         2 . The electrodeionization apparatus of  claim 1 , wherein the effective resistance of the first concentrating compartment is about the same as the effective current resistance of the second concentrating compartment. 
     
     
         3 . The electrodeionization apparatus of  claim 1 , further comprising a source of an acidic solution in fluid communication with an inlet of the first concentrating compartment. 
     
     
         4 . The electrodeionization apparatus of  claim 1 , wherein the cation exchange media comprises weak acid cation exchange resin. 
     
     
         5 . The electrodeionization apparatus of  claim 1 , wherein the anion exchange media comprises weak base anion exchange resin. 
     
     
         6 . An electrodeionization apparatus comprising:
 a depleting compartment;   a first concentrating compartment in ionic communication with the depleting compartment, the first concentrating compartment comprising media with a first effective current resistance; and   a second concentrating compartment in ionic communication with the depleting compartment, wherein a portion of the second concentrating compartment comprising media with a second effective current resistance greater than the first effective current resistance.   
     
     
         7 . The electrodeionization apparatus of  claim 6 , wherein the effective resistance of the at least a portion of the second concentrating compartment is at least two times greater than the first effective resistance. 
     
     
         8 . The electrodeionization apparatus of  claim 6 , wherein the second concentrating compartment comprises inert media. 
     
     
         9 . A method of assembling an electrodeionization apparatus comprising:
 introducing electroactive media in a concentrating compartment of the electrodeionization apparatus; and   introducing electroactive media in a depleting compartment of the electrodeionization apparatus,   wherein the electroactive media in at least one of the concentrating compartment and the depleting compartment comprises inert media in an amount that adjusts the effective current resistance of at least a portion of the at least one of the concentrating compartment and the depleting compartment.