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

Abstract The photocatalytic reduction of Hg(II) in air-equilibrated aqueous suspensions of TiO 2 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 TiO 2 powders. About 100 ppm Hg(II) is efficiently removed within 30 min from air-equilibrated solution at pH 4. The separation for Cr(VI)/Hg(II) mixtures can be achieved via UV/TiO 2 photocatalysis. Photocatalytic activities of two commercially available TiO 2 (Degussa P25 and Hombikat UV100) were also compared for different light intensities and catalyst loadings.