No abstract

No abstract

No abstract

A series of binary Mn-based materials (Fe-MnO x , Cu-MnO x , Cr-MnO x , and Mo-MnO x ) were prepared by the coprecipitation method, and the mechanism for elemental mercury (Hg 0 ) removal of Cr-MnO x in the absence and presence of SO 2 was investigated. The physicochemical structure properties of the fresh as well as spent Cr-MnO x samples were well characterized by the methods of N 2 physisorption, XRD, SEM-EDS, FTIR, H 2 -TPR, XPS, and TPD. The experiment results revealed that the loading of Cr into/onto MnO x yielded above 90% of Hg 0 removal efficiency in the presence of SO 2 at 120 °C. However, the appearance of SO 2 would lead to the formation of chromium sulfate/sulfite and manganese sulfate/sulfite although much superior SO 2 resistance was obtained. According to the N 2 physisorption and XRD characterization results, Cr doping can enlarge the BET surface area of MnO x when Cr was doped into/ onto MnO 2 , and the MnCrO 4 mixed oxide material was produced. Moreover, the H 2 -TPR result exhibited that Cr loading into/onto MnO x enhanced the redox property of Cr-MnO x mixed oxides and many more easily reduced species appeared in the mixture. The larger surface area and an abundance of reactive species could benefit from excellent performances of Hg 0 removal and superior SO 2 resistance although the DFT calculation showed almost the same adsorption energies of Hg 0 on MnO 2 (110) and Cr-MnO 2 (110) surfaces. The DFT calculation exhibited that the adsorption energy of SO 2 on the surface of Cr-MnO 2 (110) was much lower than that on MnO 2 (110), implying that Cr doping into MnO 2 would decrease the adsorption behavior of SO 2 , thereby improving its SO 2 resistance performance.