Hg oxidation reaction mechanism on Fe2O3 with H2S: Comparison between theory and experiments

Study of Hg0 removal characteristics on Fe2O3 with H2S

“…In curve C, three obvious endothermic peaks at 430°C, 470°C and 560°C can be observed, which show that at least three new substances generated at 230°C. It fits well with the results of our TPD tests [16].…”

“…Recently, our computational work also demonstrated the reaction mechanism of elemental mercury adsorption on Fe 2 O 3 in the presence of H 2 S, which drawn a conclusion that Eley-Rideal mechanism with H 2 S pre-adsorption is the most probable [12]. Simultaneously, we have verified it by a series of experiments and affirmed that either Fe 2 O 3 or H 2 S is indispensable for the elemental mercury removal [16]. Nevertheless, the effect of reaction temperature on removing mercury is still unknown.…”

Experimental Study on the Mercury Removal of a H2S-Modified Fe2O3 Adsorbent

“…It can be seen from the figure that the original Fe 2 O 3 loses the mercury removal ability after 20 min, while the mercury removal performance of H 2 S-modified Fe 2 O 3 adsorbents is significantly improved with the increase of vulcanization temperature. Xue et al demonstrated that Hg 0 prefers to bind with the Fe atom on both α-Fe 2 O 3 and γ-Fe 2 O 3 surface in the way of physisorption. Galbreath et al indicated that α-Fe 2 O 3 fails to change the form of mercury and γ-Fe 2 O 3 could facilitate the oxidation of mercury.…”

“…Among them, Fe 2 O 3 , as a commonly used desulfurization adsorbent, has been well studied in mercury removal under reductive atmosphere, showing excellent mercury removal performance. Some studies have suggested that H 2 S can boost the mercury removal ability of iron oxide, but the mercury removal ability of Fe 2 O 3 itself is weak relying on physical adsorption. , Tao et al investigated Hg 0 adsorption mechanism on the α-Fe 2 O 3 surface with H 2 S using density functional theory calculations and demonstrated that the Eley–Rideal mechanism is the most suitable reaction process. Liu et al investigated the role of H 2 S on the simultaneous reaction of Hg 0 + H 2 S + Fe 2 O 3 from an experimental perspective and deduced the foundational mercury adsorptive products through the element valence changes before and after the reaction but failed to give the specific reaction process.…”

Application of computational chemistry in understanding the mechanisms of mercury removal technologies: a review

“…In addition, a series of adsorption experiments has been carried out to verify the mechanism. 133 H 2 S and Fe 2 O 3 are both indispensable factors for the high removal efficiency of Hg 0 , and Fe 2 O 3 behaves much more actively in Hg 0 adsorption under the influence of H 2 S. Hg adsorption experiments on H 2 S pre-adsorbed a-Fe 2 O 3 shows that H 2 S can be adsorbed on the surface of Fe 2 O 3 , and the adsorbed H 2 S plays a dominant role in subsequent Hg 0 removal, which is in good agreement with the results of theoretical calculations.…”