A removal efficiency of vapor-phase elemental mercury by TiO2 irradiated using various light sources was investigated. The effective surface area of TiO2 for Hg adsorption and UV radiation was increased by packing the adsorption bed with mixture of TiO2 and glass beads. A rotating-type reactor was specially designed to maximize the photocatalyst's exposure to the light source. For three types of commercially available TiO2, more than 99% of initial Hg was removed under all the light sources tested except for the blue light still achieving a Hg removal efficiency close to 85%.