Catalytic effect of ammonia-containing species on water splitting during electrodialysis with ion-exchange membranes

摘要: Abstract It is known that some components of the bathing solution can enhance water splitting at depleted solution/ion-exchange membrane interface via protonation/deprotonation reactions with water. In this paper, we show not only presence such important, but also a mechanism ensuring their sufficiently high concentration near surface. A comparative study electrochemical behavior Neosepta® homogeneous cation-exchange CMX and an anion-exchange AMX membranes (Astom, Japan) in 0.02 M KCl or NH4Cl solutions carried out. The NH4+/NH3 couple effective catalyst splitting. deprotonation reaction rate constant NH4+ ions, which limits splitting, about 10 s−1. almost 6 orders magnitude greater than for direct dissociation free solution. comprehensive characterization systems made: voltammetry, chronopotentiometry, impedancemetry, pH-metry (including color indication pH internal solution). found essentially higher difference rates insignificant. reason weak effect on both NH3 species very low its surface if current density close to limiting value. As membrane, ammonia-containing be transported from enriched by back “facilitated” diffusion through transport plays crucial role occurrence rapid