CHED 1089 |
| Iron species play a unique role in environmental chemistry. The kinetics of hydrolysis of micromolar Fe(III) were investigated by evaluating the change in [Fe(III)]. Each experiment was performed using a series of aqueous FeCl3 solutions of a certain level; at set time intervals, the Fe(III) in a solution was reduced by hydroxylamine and then analyzed for [Fe(II)] spectrophotometrically. [Fe(II)] decreased with time, following apparent first-order kinetics. The t1/2 varies linearly with initial [Fe(III)]. The Fe(III) decrease occurred only above a certain pH depending on initial [Fe(III)]. The pH of the Fe(III) solutions decreased simultaneously by ~0.1-0.2. The kinetics of the [Fe(III)] decrease remained unchanged in the presence of 0.1 and 0.01 M KCl, but 0.1 M KCl produced more reproducible kinetics. We hypothesize that the Fe(III) species are polymerizing into hydroxylamine irreducible forms. This hypothesis is supported by increasing UV absorbance and decreasing pH of the Fe(III) solutions. |
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Undergraduate Research Poster Session: Environmental Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |