Synergistic effect between H2O and SO2 on mercury removal by activated carbon in O2/CO2 conditions

Wang, Hui; Shen, Chun; Duan, Yufeng; Ying, Zhanfeng; Li, Ya‐Ning

doi:10.1002/jctb.5866

Cited by 14 publications

(4 citation statements)

References 46 publications

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“…However, the increase in the H 2 O concentration forms a water film on the surface of the adsorbent, intensifying the isolation of Hg 0 and CO 2 . At the same time, an ample amount of H 2 O can provide additional electrons (e – ) on the surface of the adsorbent, leading to a reduction reaction with Hg 2+ , as shown in eq . normalHg 2 + + 2 normale − → normalHg 0 The influence of H 2 O on the adsorption state of mercury is shown in Figure . Three distinct desorption peaks are observed on the surface of the coke samples, and the main mercury adsorption products are Hg 0 and HgO.…”

Section: Resultsmentioning

confidence: 99%

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Investigation of Mercury Removal Behavior by Modified Biomass Coke in Oxy-fuel Combustion Flue Gas

An,

Le,

Zhong

et al. 2024

Energy Fuels

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The presence of circulating flue gas in oxy-fuel combustion leads to mercury pollution. Acid−chlorine-modified biomass coke was used to prepare mercury adsorbents. The influence of individual flue gas components (HCl, NO, SO 2 , and H 2 O) and complex flue gas on the behavior of modified straw coke for mercury removal under an oxy-fuel combustion atmosphere was studied. The mechanism of the flue gas reaction with mercury was investigated using temperature-programmed desorption (TPD) characterization. The density functional theory (DFT) was employed to study the mechanism of mercury removal by the adsorbent. The results showed that H 2 O has a dual effect on mercury removal: the low concentrations of H 2 O promote mercury removal, while moderate to high concentrations of H 2 O inhibit it. HCl and NO exhibited promotional effects on mercury removal. SO 2 competed with Hg 0 for active adsorption sites or adsorbed on the surface of the adsorbent, consuming active oxygen species and chlorinated functional groups to inhibit the adsorption and oxidation of Hg 0 . Under the atmosphere of complex flue gas, H 2 O and SO 2 inhibited the generation of highly oxidizing intermediate products from HCl and NO. Additionally, the coexistence of H 2 O and SO 2 generated H 2 SO 4 , further blocking the surface pore structure and hindering the diffusion of Hg 0 on the adsorbent surface. The result of the electron localization function (ELF) indicated that the introduction of O and Cl atoms can form stable covalent compounds (C�O and C−Cl) through bonding with the carbonaceous surface, serving as favorable chemical adsorption sites. The high reactivity of Cl induces Hg 0 adsorption, and the presence of O atoms not only acts as a chemical adsorption site but also activates the reactivity of Cl atoms, promoting the efficiency of mercury removal. This study provided a theoretical basis for the application of mercury adsorbents in oxy-fuel combustion fuel gas.

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Section: Resultsmentioning

confidence: 99%

“…However, the increase in the H 2 O concentration forms a water film on the surface of the adsorbent,40 intensifying the isolation of Hg 0 and CO 2 . At the same time, an ample amount of H 2 O can provide additional electrons (e − ) on the surface of the adsorbent, leading to a reduction reaction with Hg 2+ ,41 as shown in eq 21.…”

mentioning

confidence: 99%

Investigation of Mercury Removal Behavior by Modified Biomass Coke in Oxy-fuel Combustion Flue Gas

An,

Le,

Zhong

et al. 2024

Energy Fuels

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“…Carbon dioxide is used to carry the mercury at a flow rate of 200 mL/min. The basic atmosphere is 70% CO 2 + 6% O 2 , while the equilibrium gas is Ar. , The inlet mercury concentration is kept at 54.40 μg/m 3 and the bed height is 3 mm. The mercury measurement apparatus is based on the QM208B based on the CVAAS method, which has a measurement range and sensitivity of 0.1–100 and 0.03 μg/m 3 , respectively.…”

Section: Experiments and Methodsmentioning

confidence: 99%

“…The basic atmosphere is 70% CO 2 + 6% O 2 , while the equilibrium gas is Ar. 37,38 The inlet mercury concentration is kept at 54.40 μg/…”

Section: Experimental Device For Mercurymentioning

confidence: 99%

Multiscale Understanding of the Mechanism of Mercury Removal by Acid–Chlorine-Modified Biomass Coke: Experiments and Simulations

Le,

Wang,

Zeng

et al. 2023

Energy Fuels

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Coal-fired power plants are a significant source of mercury pollution, necessitating the development of inexpensive and efficient adsorbents for mercury removal. This work proposes the preparation of an adsorbent using acid-chlorine-modified rice straw coke for this purpose. The characterization of the adsorbent shows that the modification increases the surface pore structure and makes the surface carry abundant oxygen-containing functional groups, which is conducive to improving the mercury removal capacity of the adsorbent. This work studies the effects of the acid–chlorine ratio, mass ratio, inlet mercury concentration, and reaction temperature on the desorption performance of modified rice straw coke and investigates the mechanism of mercury removal by combining the kinetic model and density functional theory. The results demonstrate that the optimal effect of the combined acid–chlorine modification is achieved at an acid–chlorine ratio and mass ratio of 1:2. The reaction temperature has a significant effect on the efficiency of mercury removal, and the increase of the inlet mercury concentration can promote mercury removal. The mercury adsorption process is primarily controlled by surface mass transfer and chemisorption, with chemisorption being the critical control step. The introduction of Cl and O atoms through modification creates doped structures that are highly conducive to mercury adsorption. The Cl atom exhibits greater reactivity toward the Hg atom, facilitating the removal of mercury. The presence of O atoms not only increases the abundance of oxygen-containing functional groups on the surface, but also enhances the activity of the Cl atoms. These findings provide valuable theoretical support for the application of biomass coke in the field of mercury removal, addressing mercury pollution associated with coal-fired power plants.

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Acid treatment for enhancing Hg0 removal efficiency of chlorine-loaded biochar: mechanism and kinetic analysis

Zhang,

Wang,

Yang

et al. 2023

Environ Sci Pollut Res

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Synergistic effect between H₂O and SO₂ on mercury removal by activated carbon in O₂/CO₂ conditions

Cited by 14 publications

References 46 publications

Investigation of Mercury Removal Behavior by Modified Biomass Coke in Oxy-fuel Combustion Flue Gas

Investigation of Mercury Removal Behavior by Modified Biomass Coke in Oxy-fuel Combustion Flue Gas

Multiscale Understanding of the Mechanism of Mercury Removal by Acid–Chlorine-Modified Biomass Coke: Experiments and Simulations

Acid treatment for enhancing Hg0 removal efficiency of chlorine-loaded biochar: mechanism and kinetic analysis

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