A study of the photocatalytic oxidation of humic acid on anatase and mixed-phase anatase-rutile TiO2 nanoparticles

Abstract

In this study, slurry photocatalytic oxidation process was investigated for natural organic matter removal from aqueous humic acid solutions by using different titanium dioxide (TiO<inf>2</inf>) under UV-A irradiation. Bench scale experimental studies were conducted at different humic acid concentration at the range of 10-50 mg/L and different pH. Anatase and mixed-phase anatase-rutile TiO<inf>2</inf> nano particles used in the photocatalytic reactor. The results were evaluated in terms of the parameters that are specific to organic matter content such as dissolved organic carbon concentration, ultraviolet absorbance at 254 nm (UV<inf>254</inf>), specific ultaviolet absorbance at 254 nm, and color (VIS<inf>400</inf>). It was observed that increasing humic acid concentration decreases photocatalytic degradation efficiency. The reactivity of the mixed-phase anatase-rutile (Degussa P-25) TiO<inf>2</inf> was greater than individual anatase particles and the highest efficiency was observed at pH 3 for anatase TiO<inf>2</inf>. © Springer Science+Business Media B.V. 2009. © 2010 Elsevier B.V., All rights reserved.