Direct Electrolytic Process Preparation Of Potassium Ferrate

The iron (VI) derivation, potassium ferrate (VI) (Fe (VI)) has properties such as oxidizing power, selectivity, and a non-toxic by-product Fe (III), that make potassium ferrate (VI) an environmentally friendly oxidant for several applications. Potassium ferrate has been considered for years to treat with natural waters and wastewaters, because of its environmental friendly properties and its high efficiency. Fe (VI) is also a selective oxidant for a large number of organic compounds with Fe (III) as a by-product. Fe (VI) therefore has a role in greener technology for organic synthesis. Moreover, Ferrate has also been recently used in a new class of"super-iron"batteries, referred to as super-iron batteries, there use the Fe(VI)/Fe(III) system as anode material. In this paper we reported an electrochemical method generation of ferrate.In this study it reported an electrochemical generation of ferrate by dissolution of a new material. The ferrate concentration and the current efficiency are substantially larger for this iron electrode than for other electrodes reported in previous work at higher current densities (50-100 mAcm^-2), it indicating the beneficial effect of using this material iron.It discussed the influence of current density, electrolyte composition and concentration, temperature, electrolysis time, anode material and anode activated assistant on current efficiency during ferrate electrochemical production. The current efficiency increased obviously with rising electrolyte temperature. The effect of different solutes on the current efficiency of ferrate production varied apparently at different temperatures. For the solution of 16MNaOH, the current efficiency increased and reached its maximum at 35℃, then decreased dramatically with increasing temperature, while the content of ferrate remarkably and that of Fe(OH)₃ increased. However the case was not that at all for the solution of 16MKOH. The current efficiency was so low at 25℃that no obvious solid K₂FeO₄ was observed. But it increased greatly with the increasing temperature higher than 35℃, the current efficiency increased and reached its maximum at 60℃. It indicated optimum parameters effect on the yield for the electrochemical generation of ferrate were: 100mAcm^-2,16MKOH,60℃and 2h. The side reaction, that is, OER, play a role of obstacle for the process of electro-generation of ferrate.The key to ensure the reuse of anolyte was removing ferric hydroxide from the anolyte which was produced by the decomposition of ferrate. It was indispensable to supply solid KOH to anolyte continually or in batches white operating for a long time. Solid K2FeO4 produced should be separated as quickly as possible from anolyte by filtration or centrifuge after electrolysis. It remained stable only by rapid removal of water and alkaline from it. The purity of solid K2FeO4 was above 90% which was separated from anolyte only by removal of water and alkaline without any purification. Solid K₂FeO₄ with purity being 97.6% can be obtained by recrystallization.