Simultaneous removal of elemental mercury and NO from flue gas by the CeO2/TiO2 catalysts and the mechanism investigation

Mercury pollution has become one of the high-profile environmental problems in the world. A series of CeyTi catalyst were synthesized by sol-gel method, and the process of simultaneous conversion of NO and removal of mercury (Hg-0) in the flue gas was studied. BET, SEM, and XRD were used to systematically detect the physicochemical properties of the catalysts, which show that excessive Ce loading would make its specific surface area reduce. The NO conversion efficiency would increase with the increase of the Ce loading. The optimal Ce/Ti mass ratio was 0.3. A part of the adsorbed NO would be oxidized by the active oxygen species on the catalyst surface to produce a certain amount of nitrogen-containing substances, such as NO+, NO3-, or NO2. The produced substances could promote the adsorption and oxidation of Hg-0. The NO conversion was very dependent on the oxygen in the flue gas. The activity of the Ce0.3Ti catalyst was promoted in the presence of O-2. SO2 and H2O would inhibit the reaction of NO conversion and Hg-0 removal. The mechanisms of the catalytic system have been proved via the Mars-Maessen mechanism.

Automated summary

The study found that in the catalytic process of NO removal in flue gas, the NO conversion efficiency of Ce0.3Ti catalyst will increase with the increase of Ce loading, and active oxygen can promote the adsorption and oxidation of Hg-0.