title: Effect of the cathode material on the removal of nitrates by electrolysis in non-chloride media.
abstract: In this work, the effect of the cathode material (conductive diamond, stainless steel, silicon carbide, graphite or lead) and the current density (150-1400 A m(-2)) on the removal of nitrates from aqueous solutions is studied by electrolysis in non-divided electrochemical cells equipped with conductive diamond anodes, using sodium sulphate as the electrolyte. The results show that the cathode material very strongly influences both the process performance and the product distribution. The main products obtained are gaseous nitrogen (NO, N(2)O and NO(2)) and ammonium ions. Nitrate removal follows first order kinetics, which indicates that the electrolysis process is controlled by mass transfer. Furthermore, the stainless steel and graphite cathodes show a great selectivity towards the production of ammonium ions, whereas the silicon carbide cathode leads to the highest formation of gaseous nitrogen, which production is promoted at low current densities.
authors.affiliation: Department of Chemical Engineering, Faculty of Chemical Sciences, University of Castilla-la Mancha, Avda. Camilo José Cela, 12. 13071 Ciudad Real, Spain.
authors.forename: Engracia
authors.initials: E
authors.lastname: Lacasa
authors.forename: Pablo
authors.initials: P
authors.lastname: Cañizares
authors.forename: Javier
authors.initials: J
authors.lastname: Llanos
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Rodrigo
mesh_terms: D017554:Carbon Compounds, Inorganic / Q000032:analysis; D002712:Chlorides / Q000737:chemistry; D018130:Diamond / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D004572:Electrolysis / Q000379:methods*; D006108:Graphite / Q000032:analysis; D007854:Lead / Q000032:analysis; D008956:Models, Chemical; D009566:Nitrates / Q000302:isolation & purification*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D017655:Silicon Compounds / Q000032:analysis; D013193:Stainless Steel / Q000737:chemistry
chemical_list: D017554:Carbon Compounds, Inorganic; D002712:Chlorides; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D017655:Silicon Compounds; D013193:Stainless Steel; D007854:Lead; D018130:Diamond; D006108:Graphite; C022088:silicon carbide