CONICET | Buscador de Institutos y Recursos Humanos

The presence of high nitrate concentration in water can be dangerous to the human health. The electrocatalytic process to reduce nitrate can be a promising treatment method to minimize the presence of this ion in water. In this work, different sponge electrodes (Ni, Ni-Cu, Ni-Pd, Ni-Cu-Pd and Ni-Pd-Cu) were tested for the treatment of solutions containing high nitrate concentrations (135.5 N-mg L-1). The electrodes comprise nickel (Ni) sponges chemically coated with copper (Cu) and/or palladium (Pd). A dual-chamber cell (DCC), separated by a cation-exchange membrane, was used to the nitrate reduction experiments. The obtained results indicated that nickel sponge electrodes coated with Pd and Cu are encouraging materials to achieve nitrate reduction. The highest nitrate reduction (44%) was obtained with a Ni-Cu electrode being nitrite the main product generated. With the Ni-Pd-Cu electrode it was obtained the major ammonium formation (28 N-mg L-1). The pH adjustment to 6-6,5 increased the gaseous compounds formation (33 N-mg L-1). The results show that the process studied here can be used either as a first step treatment, to reduce nitrate to other chemical compounds, or as a final treatment, producing ammonium or nitrogen, when solutions of high nitrate concentration are being treated.