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

In this study, we synthesized a Ce-modified Mn/HZSM-5 adsorbent via the ultrasound-assisted impregnation for Hg capture. Given the addition of 15% CeO, ~ 100% Hg efficiency was reached at 200 °C, suggesting its promotional effect on Hg removal. The doped Ce introduced additional chemisorbed oxygen species onto the adsorbent surfaces, which facilitated the oxidation of Hg to HgO. Even though adding CeO 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 removal performance within the whole investigated temperature range. During the Hg capture process, chemisorption was predominant with Mnoperating as the main active site for oxidizing Hg to Hg. Finally, the 15Ce-Mn/HZSM-5 adsorbent exhibited good recyclability and stability. However, its tolerance to HO and SO appeared relatively weak, suggesting that some modification should be conducted to improve its practicality.