Effect of water vapor and α -Fe 2 O 3 on elemental mercury removal performance over cerium oxide modified semi coke

Abstract Cerium modified semi coke adsorbent (Ce/SC) was prepared by impregnation method and a bench-scale fixed bed reactor was used to study the effect of H 2 O vapor and α- Fe 2 O 3 on elemental mercury removal efficiency over Ce/SC. Characterizations of X-ray powder diffraction (XRD), hydrogen temperature programmed reduction (H 2 -TPR) and X-ray photoelectron spectroscopy (XPS) were conducted to investigate the mechanism of elemental mercury removal. The adsorption results showed that H 2 O had a negative effect on the oxidation activity of the adsorbent. H 2 O can be dissociated on the surface of CeO 2 with partial lattice oxygen transformation into Ce–OH functional groups which led to the decrease of its oxidation activity, and thus resulted in the inhibitory effect of mercury removal efficiency. The addition of α- Fe 2 O 3 had no significant effect on mercury removal over Ce/SC. The mercury removal efficiency of Ce/SC was decreased when the water vapor and α- Fe 2 O 3 existed simultaneously. However, the decrease rate was much lower than that of water vapor conditions alone mainly due to the interaction between water vapor and α- Fe 2 O 3 increased the content of the surface chemical adsorbed oxygen, and thus the oxidation activity and elemental mercury removal performance of Fe 2 O 3 were promoted.