Study On Preparation And Electrochemical Performance Of Ferrate (Ⅵ)

Ferrate which has very strong oxidizing is hexavalent salt of iron. It has been widelyapplicated as wastewater treatment agent and selective oxidant of organic matter and so on,besides the final product is full of evironment friendly characteristic. In recent years, theresearch of the high iron acid salt which was as electrode activity materials has gainedabound results in electrical chemistry and has attracted a great attention to scholars. In thisartical, ferrate was prepared by Hypochlorite Method，and the best technology parameterswas determined through the discussion on the influence factors of preparation. Thesamples were quantitative analysed and characterize by XRD and IR. The capacitancematerial performance of the ferrate as electrode activity was also discussed.K₂FeO₄was prepaerd using Hypochlorite Method by KMnO₄, HCl and Fe（NO₃）₃，andBaFeO₄was prepared with metathesis reactions by Ba（OH）₂and K₂FeO₄.Through theexperimental conclusion:when reaction time is1h, reaction temperature is35℃, ironsource is Fe（NO₃）₃, physico-chemical process dosing quantity is85%, the purity ofproducts K₂FeO₄can reach to90%and the yield92%. When the reaction temperaturecontrol at0℃and the concentration of KOH solution is4%, the purity of BaFeO₄canreach to92%. We can know the main products is ferrate through the XRD and infraredmapping characterization.We use N-methyl Imidazolyl as raw material to prepare two imidazole medicamentionic liquids [BMIM]BF₄and [BMIM]PF₆through the two foot work. And then throughelectrochemical window testing, conductivity testing and infrared spectrum to characterizethe two imidazole medicament ionic liquids. The results show that the product of synthesisis the target product. The electrochemical window and conductivity of [BMIM]BF₄and[BMIM]PF₆is4.4V,4.3mS/cm and4.7V,1.57mS/cm.This experiment use K₂FeO₄as electrode materials and use alkaline solution and ionicliquid, as electrolyte solution. Then take these in three electrodes system to discusselectrochemical performance of K₂FeO₄through the cycle current-voltage, constantcurrent charge and discharge and exchange impedance test. We can find that the moreappropriate as high iron electrode electrolytes is [BMIM]BF₄, followed by [BMIM]PF₆,and finally KOH （14mol/L）. Specific capacitance of high iron acid potassium electrodescan be up to374F/g when the current density of KOH solution is5mA/cm². High ironelectrodes in50cycle times has the high frequency of circular arc radius area increases and the low frequency slope decrescent compared to20cycle times.At the same timeelectrode reaction have started to load transfer of control into later spread control.We can study electrode discussion of BaFeO₄as the same testing of K₂FeO₄.We canget higher specific capacitance through CV test as the same scanning conditions of high iniron acid potassium. Through electrodes in [BMIM]BF₄and [BMIM]PF₆electrolytesolution filling the constant flow put test we find [BMIM]BF₄is more suitable forelectrolytic solution.After exchange impedance test we know the series resistance of KOH,[BMIM]PF₆and [BMIM]BF₄is1.65,0.8and0.3.. And the whole electrodereaction controlled by diffusion.