Stability of Ferrate(VI) in 14 M NaOH-KOH Mixtures at Different Temperatures
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2016 American Chemical Society. The stability of ferrate(VI) (FeVIO42-, Fe(VI)) as a function of time in NaOH-KOH mixtures at different molar ratios (3:11, 7:7, 11:3, and 14:0) of 14 M ionic strength and temperature ( 30 C, 45 C, and 60 C) was determined. Measurements of stability were performed under two concentrations of Fe(VI) in mixtures. One concentration of Fe(VI) was less than its solubility (S) (i.e., [Fe(VI)] < S) while other concentration was more than the S (i.e., [Fe(VI)] > S) under different conditions of molar ratios and temperature in the mixture solutions, which resulted in homogeneous and heteogeneous phases, respectively. The homogeneous phase had only dissolved Fe(VI), while the heterogeneous phase consisted of both dissolved Fe(VI) and precipitated Fe(VI). Results of stability were compared by evaluating decay rates of different mixtures. Decay of dissolved Fe(VI) was generally lower in heterogeneous phase than in homogeneous phase. Effect of temperature on stability in homogeneous solution had no role in mixed solution, except 3:11 molar mixture solution. Implication of results in electrochemical synthesis is briefly discussed.