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Zn and Ni codeposition from wastewater

Q. Hello,

I am working on simultaneous removal of Zn & Ni ions from wastewater by an electrochemical method. The concentration of both metals are 20 ppm. When I worked in low current density the max. removal of Ni and Zn ions was 30 & 70%. By increasing the current, the Zn ions removal increased but Ni ions removal decreased significantly. How can I get the high removal of both metal ions?

Regards,

Mitra Saidi
ryerson university - Toronto, Ontario, Canada
2004

A. The answer to your question is obviously contained in your question. Don't use a constant current density in your process.

Marcus Hahn
- Lucerne, Switzerland
2004

A. A similar co-reduction requires addition of some manganese salts and varying the potential. Probably you may have to fix the potential near the 'Mn' reduction potential. Zn and Ni will co-deposit in a stoichiometric ratio. Try with KMnO4 addition and if you find anything interesting please inform me. As I am a theoretician I could not do experiment here and confirm.

Chandramohan Rathinam
SSA college - Devakottai, Tamil Nadu, India
2004

A. Have you tried to raise the pH, or used high surface area electrodes? Ni is usually removed well at initial pH~4.2,

Nael YASRI
University of Wisconsin - Fitchburg, Wisconsin, USA
May 5, 2014

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