Preparation and demercuration analysis of multi-walled carbon nanotubes supported FeS2

Ferric nitrate and thiourea were used to prepare FeS2 under solvothermal reaction conditions which were loaded onto MWCNTs (multi-walled carbon nanotubes) by physical impregnation method. The structural characteristics of the prepared samples were investigated by means of analytical methods such as SEM, XRD and XPS. The adsorption characteristics of the adsorbent on the elemental mercury in the flue gas under simulated flue gas atmosphere were studied by a fixed bed reactor. The effects of different FeS2 loading, initial mercury concentration, reaction temperature and O2, NO and SO2 on the mercury removal efficiency of the adsorbent were investigated. The results showed that the prepared FeS2 had good dispersibility and was spherical crystal. The surface was evenly covered with MWCNTs and clustered. When the loading was 10% and the reaction temperature was 70℃, the adsorption effect of FeS2/MWCNTs was the best, the highest removal efficiency could reach 100%, and the removal efficiency was 80.3% after 60min. The TPD desorption curve and XPS analysis results further indicated that Hg0 in the flue gas was oxidized to Hg2+ and was attached to the surface of the adsorbent in the form of HgS, confirming that the adsorbent was mainly chemisorbed. In addition, the mercury removal efficiency decreased with the increase of the initial mercury concentration, but the mercury adsorption capacity increased, and the highest could reach 5.1μg/g in 60min. The presence of NO and SO2 occupied the active site on the surface of the adsorbent, which was not conducive to the adsorption of Hg0, but the low concentration of NO had little effect on the overall effect of the adsorbent, and the anti-NO performance of adsorbent was better. © 2020, Chemical Industry Press Co., Ltd. All right reserved.