INCAPE   05401
INSTITUTO DE INVESTIGACIONES EN CATALISIS Y PETROQUIMICA "ING. JOSE MIGUEL PARERA"
Unidad Ejecutora - UE
artículos
Título:
Use of a two-step process to denitrification of synthetic brines: electroreduction in a dual-chamber cell and catalytic reduction
Autor/es:
ZOPPAS, F. M.; MIRÓ, E. E.; MARDER,L.; BERNARDES, A. M.; BELTRAME, T. F.; MARCHESINI, F. A.
Revista:
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
Editorial:
SPRINGER HEIDELBERG
Referencias:
Lugar: HEIDELBERG; Año: 2020 vol. 27 p. 1956 - 1968
ISSN:
0944-1344
Resumen:
Membrane Separation Processes are being currently applied to produce drinking waterfrom water contaminated with nitrate. The overall process generates a brine with highnitrate/nitrite concentration, that is usually send back to a conventional wastewatertreatment plant. Catalytic processes to nitrate reduction are being studied, but the maingoal of achieving a high selectivity to nitrogen production is still a matter of research. Inthis work, a two-step process was evaluated, aiming to verify the best combination ofoperational parameters to efficiently reduce nitrate to nitrogen. In the first step, the nitrate was reduced to nitrite by electroreduction, applying a copper electrode and different cell potentials. A second step of the process was carried out by reducing thegenerated nitrite with a catalytic process by hydrogenation. The results showed that the highest nitrate reduction (89%) occurred when a cell potential of 11 V was applied. In this condition, the nitrite ion was generated with all experimental conditions evaluated.Then, to reduce the nitrite ion formed by catalytic reduction, activated carbon fibers (ACF) and powder ã-alumina (ã-Al 2 O 3 ) were tested as supports for palladium(Pd). With the both catalysts the total nitrite conversion was obtained, being the selectivity to gaseous compounds 94% and 97% for Pd/Al 2 O 3 and Pd/ACF,respectively. Considering the results obtained, a two-stage treatment set-up to brine denitrification may be proposed. With electrochemistry an operating condition was achieved in which ammonium production can be controlled to very low values, but the reduction is predominant to nitrite. With the second step, all nitrite is converted tonitrogen gas and just 3% of ammonium is produced with the most selective catalyst.The main novelty of this work is associated to the use of a two-stage process enabling89% of nitrate reduction and 100% of nitrite reduction.