Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
581139 | Journal of Hazardous Materials | 2009 | 5 Pages |
Abstract
The electrochemical reduction of nitrate and nitrite in simulated low-level nuclear wastes containing 1.8Â M NaNO3Â +Â 0.55Â M NaNO2Â +Â 1.16Â M NaOH was studied under galvanostatic polarization on tin and bismuth cathodes. The rate of the reduction of nitrate was about the same on both metals. The selectivity (%S) to ammonia was similar on the two metals (12% at 450Â mA/cm2) and that to nitrogen 82% on Sn and 72% on Bi. On the other hand, the %S to nitrous oxide was lower on Sn (8%) than that on Bi (18%) under the same conditions. The current efficiency (%CE) on both metals was 80% when the 99% of the initial nitrogen was removed. The %CE gradually decreases as the concentration of the nitrogen containing species in the solution decreases during the electrolysis. The energy consumption for the removal of 1Â g of N was 100Â WÂ h at 450Â mA/cm2 but it can be significantly reduced by a better design of the electrolysis cell.The presence of chromate in the electrolyte, which is a known inhibitor of the cathodic reduction of nitrate, has no influence on the rate of the reduction and the distribution of the products.
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Authors
I. Katsounaros, M. Dortsiou, G. Kyriacou,