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Copper in wastewater and EIX

We are trying to remove heavy metal ion contaminants from waste water in the lab via a method called Electrochemical Ion Exchange (EIX). The method basically incorporates a resin and an electrode structure, where the goal is for the contaminant to deposit onto the resin and not the cathode. Specifically, we're trying to get rid of copper from a solution consisting of copper sulphate ⇦ this on eBay or Amazon [affil links] and water. If we want the contaminant to deposit onto the resin, and not the cathode, using a very low voltage (~.35), what would be the ideal material of the electrodes? Would it be iridium coated titanium?

Melisssa Holt
student - San Diego, California, USA
2004

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While I am not familiar with the specific piece of equipment you are using,there are two apparent problem to what you ar trying to do. First, for the IX resins, the pH must be in the correct range for the resin to absorb copper. A sulfuric acid solution probably has a pH that is too low for this. Second, if you run any DC current through a solution of copper in sulfuric acid then you will deposit copper on the cathode.

The only technology of this type that I have heard for this application uses the resin to absorb the copper at rinse water pH values with no voltage or current, and then regenerates the resin by generating acid in situ with the electric current in a cell that has a membrane separator.

Lyle Kirman
consultant - Cleveland Heights, Ohio
2004