Removal of elemental mercury by photocatalytic oxidation over La2O3/Bi2O3 composite

La2O3/Bi2O3 photocatalysts were prepared by impregnation of Bi(2)O(3 )with an aqueous solution of lanthanum precursor followed by calcination at different temperatures. The composite materials were used for the first time for the photocatalytic removal of Hg-0 from a simulated flue gas under UV light irradiation. The results showed that the sample containing 6 wt.% La-2 O-3 and calcined at 500 degrees C has the highest dispersion of the active sites, which was promoted by the strong interaction with the support (i.e., the formation of Bi-O-La species). Since they are fully accessible on the surface, the material also exhibits excellent optical properties while the heterojunction formed in La2O3/Bi2O3 promotes the separation and migration of photoelectron-hole pairs and thus Hg-0 oxidation efficiency is enhanced. The effects of the various factors (e.g., the reaction temperature and composition of the simulated flue gas (i.e., O-2, NO, H2O, and SO2)) on the efficiency of the Hg-0 photocatalytic oxidation were investigated. The results demonstrated that O(2 )and SO2 enhanced the efficiency of the reaction while the reaction temperature, NO, and H2O had an inhibitory effect. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.