ACTIVATION PARAMETERS OF FERRYL ION REACTIONS IN AQUEOUS ACID-SOLUTIONS

The temperature dependence of the oxidation kinetics of Fe2+ by O-3 at pH 0-3 was studied by stopped-flow technique in the temperature range 5-40 degrees C. Activation parameters of the reactions involved in fo rmation and decay of the ferryl ion (iron(IV)), FeO2+ are determined. The reaction of Fe2++FeO2+ was found to branch into two channels formi ng iron(III)-dimec Fe(OHFe4+ and Fe3+. The yield of the dimer, Fe(OHFe 4+, increases with temperature on the expense of the Fe3+ yield. On th e basis of the overall rate constant and relative yield of Fe(OHFe4+ t he activation energy is determined for both channels. The activation p arameters of the hydrolysis of the ferryl ion and its reaction with H2 O2 were also determined. (C) 1997 John Wiley & Sons, Inc.