Photocatalytic reduction of Hg(II) on two commercial TiO2 catalysts

Abstract

The photocatalytic reduction of Hg(II) in air-equilibrated aqueous suspensions of TiO2 under UV-illumination were studied. The amount of Hg(II) photo-reduced is affected by the pH of solution, the amount of the hole-scavengers, the concentration of chloride, mass of the catalyst, and incident light intensity. Hg(0) was detected during the photocatalytic reduction of Hg(II). The reduction rate of Hg(II) was controlled by the amount of Hg(II) adsorbed onto the TiO2 powders. About 100ppm Hg(II) is efficiently removed within 30min from air-equilibrated solution at pH 4. The separation for Cr(VI)/Hg(II) mixtures can be achieved via UV/TiO2 photocatalysis. Photocatalytic activities of two commercially available TiO 2 (Degussa P25 and Hombikat UV100) were also compared for different light intensities and catalyst loadings. © 2003 Elsevier Ltd. All rights reserved.