New electrodes for silver(II) electrogeneration: Comparison between Ti/Pt, Nb/Pt, and Nb/BDD

Electrochemical processes based on the regeneration of silver(II) are very efficient for the destruction or dissolution of persistent substances. The aim of this work is to assess new anode materials to replace the conventional platinum electrode. The electrochemical generation of Ag(II) by oxidation of Ag(I) in HNO3 (6 mol/L) was evaluated at boron doped diamond on niobium substrate (Nb/BDD) anode and results are compared with those obtained on Ti/Pt and Nb/Pt anodes. The performance of these anodes was evaluated in a filter press reactor in batch operation mode. The rate of Ag(II) generation obtained on the Nb/BDD anode is similar to that obtained on platinized electrodes. A theoretical model is presented to predict the behavior of the system. Good agreement is found between experimental results and the theoretical model.

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► Nb/BDD electrode can efficiently generate silver(II) in nitric acid media.
► The comparison with Ti/Pt has shown that the generation rate was very similar.
► Simulation successfully predicted the behavior of the system.
► Competitive reactions with hydroxyl radical and Ag(II)/Ag(I) are negligible.