This study investigated the oxidation efficiency and reaction mechanisms of Hg0 under multi-pollutant environments using photothermal catalysts at the temperatures of 100-200℃. The photothermal catalytic experiments were conducted in two phases. Tthe first phase applied sol-gel method to prepare three photothermal catalysts (TiO2, 7%CeO2/TiO2, and 5%CuO/TiO2) and characterized their surface properties with SEM, EDS, TEM, SSA, XRD, XPS, and PL. The second phase investigated the effects of operating parameters on the oxidation efficiency of Hg0 at 100-200oC in a continuous-flow catalytical reactor. The operating parameters investigated in this study included reaction temperature and multi-pollutant atmosphere of NO and SO2. Experimental results indicated that TiO2 prepared by sol-gel method was mainly anatase, and the crystal size was in the range of 10-20 nm, which is characterized as nano-sized catalysts. XPS showed that the chemical adsorption oxygen (Oα) was more active than the lattice oxygen (Oβ), indicating that the chemical adsorption oxygen (Oα) was the major oxidant for Hg0 oxidation. The oxidation efficiency of Hg0 for different reaction temperatures was ordered as η100＞η150＞η200 in the atmosphere of N2+Hg0. In the atmosphere of N2+Hg0+NO, low concentration of NO (300 ppm) could enhance Hg0 oxidation. In the atmosphere of N2+Hg0+SO2, SO2 could partially occupy the active sites over the catalysts’ surface for Hg0 oxidation and inhibited the catalytic oxidation of Hg0. The results of XPS and FTIR indicated that sulfates (SO42-) were deposited on the surface of the photothermal catalysts which diminished their photothermal catalytical activity.
