Recent advances on the adsorption and oxidation of mercury from coal-fired flue gas: A review

Ishag, Alhadi; Yue, Yanxue; Xiao, Jin; Huang, Xinshui

doi:10.1016/j.jclepro.2022.133111

Cited by 33 publications

(17 citation statements)

References 154 publications

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“…This phenomenon became more significant with an increase in temperature. This was due to the gradual inactivation of the AC with increasing temperatures . When the temperature was higher than 150 °C, the deactivation phenomenon was more significant, and the adsorption capacity for heavy metals was significantly reduced.…”

Section: Resultsmentioning

confidence: 99%

“…Among these, post-combustion heavy metal adsorption control technology is currently a research hotspot. Researchers have focused on developing activated carbon (AC), kaolin, mineral oxides, and other non-carbon-based adsorbents. − AC is widely used because of its rich surface functional groups and pore structure. However, it exhibits low adsorption efficiency at high temperatures, limited regeneration, poor fly ash reusability, and high operating costs .…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have focused on developing activated carbon (AC), kaolin, mineral oxides, and other non-carbon-based adsorbents. − AC is widely used because of its rich surface functional groups and pore structure. However, it exhibits low adsorption efficiency at high temperatures, limited regeneration, poor fly ash reusability, and high operating costs . Therefore, developing new high-temperature-resistant and efficient non-carbon-based adsorbents is significant for developing heavy metal adsorption control technologies after combustion.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas

Gai

Zhan

et al. 2023

ACS Omega

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Developing non-carbon-based adsorbents is essential for removing heavy metals from post-incineration flue gas. In this study, a new high-temperature-resistant adsorbent-activated boron nitride (BN) was prepared using precursors combined with a high-temperature activation method. The adsorption characteristics of BN for Zn, Cu, and Cd in simulated flue gas and sludge incineration flue gas were investigated using gas-phase heavy metal adsorption experiments. The results showed that BN prepared at 1350 °C for 4 h had defect structures, abundant pores, functional groups, and a high specific surface area of 658 m2/g. The adsorption capacity of BN in simulated flue gases decreases with increasing adsorption temperature, whereas it is always higher than that of activated carbon (AC). The total adsorption capacities for Zn, Cu, and Cd were the highest at 50 °C with 48.3 mg/g. BN had strong adsorption selectivity for Zn, with a maximum adsorption capacity of 54.45 mg/g, and its adsorption process occurred mainly on the surface. Cu and Cd inhibited Zn adsorption, leading to a decrease in the Zn adsorption capacity. In sludge incineration flue gas, BN can quickly reach adsorption equilibrium. The BN had a synergistic disposal capacity for heavy metals and fine particulate matter. The maximum adsorption capacity was reduced compared to the simulated flue gas adsorption capacity, which was 5.1 mg/g. However, BN still exhibited a strong adsorption selectivity for Zn, and its adsorption capacity was always greater than that of AC. The rich functional groups and high specific surface area enable BN to physically and chemically double-adsorb heavy metals.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas

Gai

Zhan

et al. 2023

ACS Omega

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“…Mercury (Hg) emission during fossil fuel consumption has posed a threat to the global environment due to its high toxicity and bioaccumulation ability. − To date, Hg removal methods, such as coal washing, thermal coal treatment, adsorption, and catalytic oxidation, have been widely studied. − Among them, the catalytic oxidation has been considered to be an effective approach to the Hg elimination. , Generally, Hg in flue gas can exist as both elemental Hg (Hg 0 ) and oxidized Hg (Hg 2+ ) in compounds, and the oxidation state of Hg is known to critically affect the efficiency of Hg removal in the flue gas treatment facility; Hg 0 is highly volatile and insoluble in water (∼50 μg/L), not being effectively eliminated, while Hg 2+ is soluble in water and can be easily removed by wet flue gas desulfurization systems. , Among many, the selective catalytic reduction (SCR) catalysts, such as TiO 2 -supported vanadia (VO x /TiO 2 ), have attracted extensive attention owing to their catalytic and economic efficiency; the use of V 2 O 5 /TiO 2 catalysts has been shown to be effective in promoting Hg oxidation under specific reaction conditions . These conditions typically include a high temperature of 623 K and the presence of oxidizing agents, such as oxygen or chlorine .…”

Section: Introductionmentioning

confidence: 99%

Change in the Electronic Environment of the VO_x Active Center via Support Modification to Enhance Hg Oxidation Activity

et al. 2023

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Oxidation of elemental Hg (Hg 0 ) is catalytically and economically an efficient way to remove the harmful Hg contained in the flue gas from coal combustion facilities. Thus, the development of a highly active V 2 O 5 /TiO 2 catalyst, which is active to the Hg oxidation, is very essential. Support modification can change the reactivity of V 2 O 5 /TiO 2 by affecting the V 2 O 5 active center which is critical to the surface−reactant interaction, so understanding the effects of support tuning methods, e.g., crystallographic phase control and reduction treatment, on the Hg oxidation activity is valuable. Herein, density functional theory calculations were performed to mechanistically investigate the change of Hg oxidation reactivity by the support tuning methods and to elucidate the change of the electronic environment at the active site. The phase control to the TiO 2 support was found to improve the Hg oxidation activity, but the reduction treatment decreased the activity, which is attributed to the change of the charge density at V 2 O 5 . Furthermore, the origin of the reactivity change was elucidated within a Sabatier-like principle that the interaction between the V site and the surface Cl critically contributes to the change of the Hg oxidation reactivity by balancing the competition between two key reaction steps of HCl dissociation and HgCl 2 desorption. Our results provide guidance to improve the activity of the VO x /TiO 2 catalyst for various reactions such as Hg oxidation and selective catalytic reduction of NO x and so on.

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“…[1][2][3] As a traditional Hg 0 treatment method, the adsorption method has some problems, such as easy adsorption saturation and difficult resolution, thereby limiting its application severely. [4,5] Although the heat treatment demonstrates excellent Hg 0 removal efficiency, it tends to damage the catalyst structure and reduce the catalyst stability. [6][7][8] Since the existing air pollutants treatment technologies cannot work efficiently, it is imperative to develop new Hg 0 emission control technology.…”

mentioning

confidence: 99%

Halogenated Ti₃C₂ MXenes Prepared by Microwave Molten Salt for Hg⁰ Photo‐Oxidation

Xie

Peng

et al. 2023

Adv Funct Materials

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Ti 3 C 2 MXenes with different halogen modifications are prepared rapidly and efficiently by microwave molten salt method, and the MXene surface functional group modification is successfully achieved to address the problems of low purity, complex functional groups, and uncontrollable energy band structure of MXenes obtained by traditional liquid phase etching. Among them, the modification of the iodine (I) functional group onto the surface of Ti 3 C 2 changes the energy band structure and band gap, resulting in easier photoexcitation and more photogenerated carriers. The increased Fermi energy is closer to the conduction band, the decreased surface work function weakens the electron confinement ability. The photogenerated carriers can migrate to the surface of the material more easily with extended lifetime, so the activity of the catalyst is improved. Further, for gaseous monomeric mercury (Hg 0 ) photo-oxidative removal, Ti 3 C 2 -I 2 exhibits 85.5% efficiency of Hg 0 photo-oxidative removal under visible light. Based on the experimental characterization and density functional theory calculations, a mechanism for the photooxidative removal of Hg° from Ti 3 C 2 -I 2 MXene is proposed, which provides a valuable strategy for studying Ti 3 C 2 MXenes in the field of photocatalysis.

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Recent advances on the adsorption and oxidation of mercury from coal-fired flue gas: A review

Cited by 33 publications

References 154 publications

Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas

Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas

Change in the Electronic Environment of the VO_x Active Center via Support Modification to Enhance Hg Oxidation Activity

Halogenated Ti₃C₂ MXenes Prepared by Microwave Molten Salt for Hg⁰ Photo‐Oxidation

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Recent advances on the adsorption and oxidation of mercury from coal-fired flue gas: A review

Cited by 33 publications

References 154 publications

Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas

Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas

Change in the Electronic Environment of the VOx Active Center via Support Modification to Enhance Hg Oxidation Activity

Halogenated Ti3C2 MXenes Prepared by Microwave Molten Salt for Hg0 Photo‐Oxidation

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Product

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Change in the Electronic Environment of the VO_x Active Center via Support Modification to Enhance Hg Oxidation Activity

Halogenated Ti₃C₂ MXenes Prepared by Microwave Molten Salt for Hg⁰ Photo‐Oxidation