Remove elemental mercury from simulated flue gas by CeO 2 -modified MnO x /HZSM-5 adsorbent

In this study, we synthesized a Ce-modified Mn/HZSM-5 adsorbent via the ultrasound-assisted impregnation for Hg 0 capture. Given the addition of 15% CeO 2 , ~ 100% Hg 0 efficiency was reached at 200 °C, suggesting its promotional effect on Hg 0 removal. The doped Ce introduced additional chemisorbed oxygen species onto the adsorbent surfaces, which facilitated the oxidation of Hg 0 to HgO. Even though adding CeO 2 led to a weakened adsorbent acidity, yet it appeared that this negative affect could be completely overcome by the enhanced oxidative ability, which finally endowed Ce-modified Mn/HZSM-5 with a satisfactory Hg 0 removal performance within the whole investigated temperature range. During the Hg 0 capture process, chemisorption was predominant with Mn 4+ operating as the main active site for oxidizing Hg 0 to Hg 2+ . Finally, the 15Ce-Mn/HZSM-5 adsorbent exhibited good recyclability and stability. However, its tolerance to H 2 O and SO 2 appeared relatively weak, suggesting that some modification should be conducted to improve its practicality.