Showing papers on "Electrodeionization published in 1995"

Polarity reversal and double reversal electrodeionization apparatus and method

Abstract: Electrodeionization apparatus having a novel polarity reversal protocol designed to provide continuous, high-quality product fluid is described. The protocol involves substitution of a recirculating fluid stream established in an ion-concentrating compartment by a fluid stream having a lower ionic concentration, while maintaining fluid flow through an adjacent ion-depleting compartment. A method and protocol for modifying the ionic makeup of compartment ion exchange material and fluids are also provided. A flow reversal protocol is also provided, during which high-quality fluid product is recovered from the inventive apparatus. The polarity reversal protocol and flow reversal protocol may each be effected separately, or the flow reversal may be introduced into the sequence of the polarity reversal protocol. The inventive electrodeionization apparatus is arranged in a novel cell pair grouping configuration and oriented such that fluid flow through an ion-concentrating compartment is in a substantially upward direction, facilitating efficient removal of gas generated in the ion-concentrating compartment.