Electrolysis of nitric acid by using a glassy carbon fiber column electrode system

The electrochemical redox behavior of nitric acid was studied using a glass y carbon fiber column electrode system, and its reaction mechanism was sugg ested and confirmed in several ways. Electrochemical reactions in less than 2.0M nitric acid was not observed. However, in more than 2.0M nitric acid, the reduction of nitric acid to nitrous acid occurred and the reduction ra te was stow so that the nitric acid solution had to be in contact with an e lectrode for a period of time long enough for an apparent reduction current of nitric acid to nitrous acid to be observed. The nitrous acid generated in more than 2.0M nitric acid was rapidly and easily reduced to nitric oxid e by an autocatalytic reaction. Sulfamic acid was confirmed to be effective to destroy the nitrous acid. At least 0.05M sulfamic acid was necessary to scavenge the nitrous acid generated in 3.5M nitric acid.