Enhancement of nitrate electroreduction using BDD anode and metal modified carbon fiber cathode

• Cu/CF and Ag/CF composites were produced and characterized.
• The amount of metal deposits depends of the functional groups on the CF surface.
• The nitrate reduction rate was very fast when the nitrite formation was high.
• The best performance of Cu/CF1000 cathode and BDD anode to reduce nitrate.

Silver and copper were electrodeposited on carbon fiber (CF) with heat treatment temperatures of 1000 and 2000 °C. Cu/CF1000 and Ag/CF1000 presented more uniform particles with higher densities than those for CF2000. This behavior was attributed to electrostatic force between Cu2+/Ag+ and CO functional group present on CF1000 surface. Nitrate electroreduction was carried out using Ag/CF or Cu/CF cathode and BDD anode. The rate-determining step of nitrate reduction was its transformation into nitrite ions. The best performance for electrochemical nitrate reduction was achieved using Cu/CF1000 resulting in 100% of nitrate reduction not to mention its low by-product formation.