Novel quantification of formation trend and reaction efficiency of hydroxyl radicals for investigating photocatalytic mechanism of Fe-doped TiO during UV and visible light-induced degradation of acid orange 7.

A detailed mechanistic investigation of the hydroxyl radical (•OH) formation and organic pollutant degradation over transition metal-doped and undoped TiO photocatalysts was performed by the quantitative measurement of •OH and the identification of intermediate products under various experimental conditions. The Fe-doped TiO as a typical subject was prepared, characterized and used to degrade an azo dye Acid Orange 7 (AO7). It is indicated that the enhanced photocatalytic activity of Fe-doped TiO for AO7 degradation was attributed to the increase in surface area, the facilitated charge transfer via Fe-dopant, and a red shift of absorbable wavelength, maintaining a great formation of •OH under visible irradiation.

[Impact of dissolved oxygen on the activity of anaerobic granular sludges].

The effect of dissolved oxygen (DO) on the methanogenic activity of anaerobic granular sludges introduced into the expanded granular sludge bed (EGSB) reactor was measured in serum flasks. Results show that the specific methanogenic activity (SMA) decreases with DO increases. At 22 degrees C, the SMA drops from 75.