P211
The effect of selected parameters on the photoproduction of O2 and H2 from a WO3-Fe2+-Fe3+ aqueous suspension
Gratian R. Bamwenda, Kazuhiro Sayama, and Hironori Arakawa
NIMC
The photoproduction of oxygen and hydrogen from an aqueous suspension containing WO3, Fe2+, and Fe3+ species was studied.
The optimum photoproduction for O2 and H2 was obtained under the following operating conditions: WO3 concentration: 8 g dm-3, [Fe3+]: 14-20 mol dm-3, pH 1.5-2.5, illumination wavelength: 200-500 nm. The illumination time to reach the stationary state was ca. 6 and 30 h for the inner- and outer- irradiation systems, respectively. In addition to these conditions, a ratio of [Fe2+]: [Fe3+] = 2 ~ 4 was found to be suitable for the simultaneous production of O2 and H2. The product yields from the annular photoreactor were usually about four times than those from an outer-irradiation photoreactor. When Fe2(SO4)3 was replaced by Fe(NO3)3 or FeCl3 as a source of Fe3+ species, higher initial O2 evolution rates were obtained but the long term yields were lower than those from dispersions containing Fe2(SO4)3.
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