Etectrosynthesis of ferrates with diamond anodes

This work is focused on the electrosynthesis of ferrates with boron-doped diamond (BDD) anodes. These compounds are oxo-anions of Fe(V) and Fe(VI) with a very high oxidant potential over a wide range of pHs, and with a great variety of industrial and environmental applications. It has been observed that the use of BDD electrodes can improve the results obtained by steel electrodes in the synthesis of ferrates. However, the results seem to be limited by the availability of oxidizable it-on species in the reagent solution. The production yield is revealed to be strongly dependent on the iron raw material, hydroxyl anions concentration, temperature, and current density. The use of iron-powder bed as iron-raw material increases the availability of oxidizableiron species and therefore allows improving the efficiency of the electrosynthesis with BDD. Likewise, current densities over 1000 A m(-2) and temperatures around 25 degrees C guaranty high current efficiencies and ferrates concentrations. (C) 2008 American Institute of Chemical Engineers.