| Abstract
| - Variation of iron species in the UV-irradiated aqueoussolution was examined in the presence of various dissolvedorganic matter (DOM). Under the irradiation at constantlight intensity, a regular oscillation in the ratio of Fe(II) tototal iron, Fe(II)/Fe(t), was observed when DOM wasperiodically added into the solution. In each cycle, theFe(II)/Fe(t) ratio increased initially and then decreased withconcomitant degradation of DOM. The Fe(II)/Fe(t) ratioapproached a constant value after the DOM was completelymineralized. The period and amplitude of the oscillationwere dependent on DOM structure and its initial concentration,but the ultimate photosteady state was not affected byDOM. It was revealed that both DOM and photoreactiveFe(III) species were indispensable for the fluctuation inFe(II)/Fe(t) ratio. The ultimate photosteady state originatedfrom the equilibrium between Fe(III) photoreduction andaerobic Fe(II) photooxidation induced simultaneously by UVirradiation. It was the DOM that disturbed these twoopposite processes, leading to the oscillation in Fe(II)/Fe(t) ratio under UV irradiation.
|
