抄録
Fenton reaction has been focused as an option of CO2 reduction to organic compounds such as alcohol. We investigated the effect of morphology of precipitates during Fenton reaction to CO2 reduction in order to establish effective and validated process. Precipitates during/after reactions were analyzed by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). Morphology of precipitates was gradually changed from ferrihydrite to schwertmannite when the reaction time and pH were increased. The chemical thermodynamics equilibrium calculation suggested that schwertmannite was the main precipitate in Fenton reaction. In the actual experiments, ferrihydrite was also formed because schwertmannite is hardly precipitated under pH sharp fluctuation associated with Fenton reaction. Reactivity between hydrogen peroxide and artificial sludge (ferrihydrite or schwertmannite) was measured by Absorptiometer using the Mutarotase-GOD method. Ferrihydrite consumed more hydrogen peroxide than schwertmannite, which suggested that hydroxyl radical was produced by the reaction between hydrogen peroxide and the surface of ferrihydrite. All experimental results showed that more CO2 was reduced to organic compounds when more ferrihydrite was formed in precipitates. These results suggested that ferrihydrite was more largely contributed to Fenton reaction than schwertmannite.
