Enhancement of Gaseous Iodine Emission by AqueousFerrous Ions during the Heterogeneous Reaction of Gaseous Ozone withAqueous Iodide.

Gaseous I2formation fromthe heterogeneous reactionof gaseous ozone with aqueous iodide in the presence of aqueous ferrousion (Fe2+) was investigated by electron impact ionizationmass spectrometry. Emission of gaseous I2increased asa function of the aqueous FeCl2concentration, and themaximum I2formation with Fe2+was about 10times more than without Fe2+. This enhancement can be explainedby the OH–scavenging by Fe3+formedfrom Fe2+ozonation to produce colloidal Fe(OH)3. This mechanism was confirmed by measurements of aqueous phase productsusing a UV–vis spectrometer and an electrospray ionizationmass spectrometer. We infer that such a pH-buffering effect may playthe key role in general halogen activations. [ABSTRACT FROM AUTHOR]