Elemental mercury removal from syngas by porous carbon-supported CuCl2 sorbents

Shen, Fenghua; Liu, Jing; Dong, Yuchen; Wu, Di; Gu, Chenkai; Zhang, Zhen

doi:10.1016/j.fuel.2018.11.016

Cited by 90 publications

(38 citation statements)

References 49 publications

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“…HgCl serves as an important intermediate during HgCl 2 formation . The reaction pathway is influenced by the interaction of HgCl with the Fe 3 O 4 surface.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Landscape of HCl-Mediated Hg⁰ Capture by Magnetite

et al. 2019

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Magnetic sorbents for elemental mercury capture from flue gas have received considerable attention due to their high efficiency as well as magnetic and regenerable properties. Magnetite (Fe 3 O 4 ) is one of the main ingredients of magnetic sorbents. Firstprinciples calculations were conducted to provide an atomic-level mechanism of HCl-mediated Hg 0 reaction over magnetite. The Fe tet1 termination of Fe 3 O 4 (111) is the thermodynamically favored surface of Hg 0 adsorption. Hg 0 prefers to chemically adsorb on the iron active sites; the energy released from Hg 0 adsorption is 135.35 kJ/mol. The strong interaction of Hg 0 with active sites is mainly attributed to the atomic-orbital resonance of a Hg atom with a Fe atom. HCl adsorption over magnetite is a spontaneous dissociation reaction to generate activated chlorine species for HgCl 2 formation. HgCl serves as a key intermediate in Hg 0 transformation. Both HgCl and HgCl 2 undergo a strongly exothermic adsorption process. The nondissociative adsorption of HgCl 2 over magnetite is closely associated with the electron sharing between Fe and Cl atoms. The HCl-mediated mercury reaction over Fe 3 O 4 is controlled by the Langmuir−Hinshelwood mechanism. The energy barriers of the HCl-mediated Hg 0 reaction on the Fe tet1 -and Fe oct2 -terminal surfaces are 229.35 and 319.74 kJ/mol, respectively. The Fe tet1 termination is more active for the HCl-mediated Hg 0 reaction than the Fe oct2 termination. Hg* + Cl* → HgCl* is the rate-determining step of the comprehensive mercury reaction over magnetite.

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“…HgCl serves as an important intermediate during HgCl 2 formation . The reaction pathway is influenced by the interaction of HgCl with the Fe 3 O 4 surface.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Landscape of HCl-Mediated Hg⁰ Capture by Magnetite

et al. 2019

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“…As estimated by the proportion of relative peak areas, the ratio of Cu(I) to Cu(II) was about 1.9, indicating that partial Cu(I) species were oxidized during the immobilization process. The Cu 2p3/2 binding energies for Cu(II) and Cu(I) were 934.6 and 932.2 eV, respectively, about 0.6 and 0.4 eV lower than that of free CuCl 2 (935.2 eV) [40] and CuCl (932.6 eV) [16] salts. Accordingly, the N1s binding energy of Cu@PCP-Phen was 400.3 eV, about 0.8 eV higher than that of N1s for PCP-Phen (Figure 4b).…”

Section: Characterization Of the Catalystmentioning

confidence: 99%

Copper supported on phenanthroline‐functionalized porous polymer as an active catalyst for the oxidative carbonylation of methanol

Lei

Leng

et al. 2019

Applied Organom Chemis

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Porous organic polymer has recently attracted tremendous interest because of its potential to combine the best features of homogeneous and heterogeneous catalysts. In this study, copper supported on phenanthroline‐functionalized porous polymer (Cu@PCP‐Phen) was prepared by a co‐polymerization method and used as a heterogeneous catalyst for dimethyl carbonate synthesis via the oxidative carbonylation of methanol. The catalyst was characterized by N2 adsorption, scanning electron microscopy, transmission electron microscopy, 13C solid‐state nuclear magnetic resonance, and X‐ray photoelectron spectroscopy, which suggested that it possessed a big surface area, hierarchical porous structure, and strong electron‐donating effect toward copper species. The Cu@PCP‐Phen catalyst showed high catalytic activity, which was significantly higher than those achieved with Cu‐based catalysts under similar reaction conditions. In addition, the catalyst can be easily separated and reused at least six times with only a slight decrease in activity. The salient features of this protocol are the simplicity in handling of the catalyst, high catalytic activity, excellent selectivity, low copper leaching, and good catalyst recyclability.

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“…These gaseous products are used for combusting for advanced power generation, , producing fine chemicals, or synthesizing fuel via the Fischer–Tropsch process . The predominant species of mercury, releasing from coal, among the gaseous products is Hg 0 due to the high temperatures and reducing atmospheres. − Given that Hg 0 has high volatility and low solubility in water, capturing elemental mercury with heterogeneous catalytic adsorbents, − especially modified carbon materials, is one of the favorable methods. CO 2 needs to be separated from syngas and condensed for storage to reduce the greenhouse effect, but trace mercury in CO 2 stream can corrode aluminum equipment , when it flows through purification and compression units.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, when CO concentration is high, it competes with Hg 0 for adsorption sites, and CO 2 does not disturb the mercury adsorption . Shen et al supposed CO has a negligible effect on a CuCl 2 -AC sorbent, whereas other researchers have suggested CO takes a passive role because it can generate deposited carbon over the adsorbent surface and block the pore structures . The CO 2 concentration in the syngas varies from 7 to 40 vol %. − When Diamantopoulou et al added 12 vol % CO 2 into a nitrogen atmosphere, the mercury-removal efficiency dropped drastically by 85%.…”

Section: Introductionmentioning

confidence: 99%

Effects of CO and CO₂ on the Removal of Elemental Mercury over Carbonaceous Surfaces

Zhou

2021

ACS Omega

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Coal gasification is a popular method for the optimization of coal utilization and the reduction of environmental pollutant emissions. However, the reductive atmosphere of its products is disadvantageous for removing elemental mercury (Hg0). Activated cokes (AC) was employed in this work for mercury capture in a reducing atmosphere. The high-temperature heating decreases the mercury-removal capability of carbon sorbents because the carbonaceous surface is becoming oxygen-depleted and micropore-decreased after the heating treatment. The mechanism of mercury adsorption in pure nitrogen follows the Mars–Maessen mechanism over the carbon sorbents. To identify the effects of carbon monoxide (CO) and carbon dioxide (CO2) on Hg0 removal, the Hg0-adsorption and thermal desorption experiments were carried in a fixed-bed reaction system. CO inhibits both the chemisorption and physisorption of Hg0. CO2 competes for the active sites, lactone groups and hydroxyl groups, and occupies the micropores, which is beneficial to adsorb Hg0 physically. When CO and CO2 coexisted, the removal efficiencies show steadier than those in monocomponent gas (only CO or CO2). CO2 can resist the negative effect of CO on Hg0 removal, to some extent, because CO2 can inhibit the oxidation and disproportionation of CO. This experimental study provides practical guidance for the development of mercury-removal technology with carbon materials in the coal gasification plant.

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Elemental mercury removal from syngas by porous carbon-supported CuCl2 sorbents

Cited by 90 publications

References 49 publications

Mechanistic Landscape of HCl-Mediated Hg⁰ Capture by Magnetite

Mechanistic Landscape of HCl-Mediated Hg⁰ Capture by Magnetite

Copper supported on phenanthroline‐functionalized porous polymer as an active catalyst for the oxidative carbonylation of methanol

Effects of CO and CO₂ on the Removal of Elemental Mercury over Carbonaceous Surfaces

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Elemental mercury removal from syngas by porous carbon-supported CuCl2 sorbents

Cited by 90 publications

References 49 publications

Mechanistic Landscape of HCl-Mediated Hg0 Capture by Magnetite

Mechanistic Landscape of HCl-Mediated Hg0 Capture by Magnetite

Copper supported on phenanthroline‐functionalized porous polymer as an active catalyst for the oxidative carbonylation of methanol

Effects of CO and CO2 on the Removal of Elemental Mercury over Carbonaceous Surfaces

Contact Info

Product

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Mechanistic Landscape of HCl-Mediated Hg⁰ Capture by Magnetite

Mechanistic Landscape of HCl-Mediated Hg⁰ Capture by Magnetite

Effects of CO and CO₂ on the Removal of Elemental Mercury over Carbonaceous Surfaces