DFT and Experimental Study on the Mechanism of Elemental Mercury Capture in the Presence of HCl on α-Fe<sub>2</sub>O<sub>3</sub>(001)

Liu, Ting; Xue, Lucheng; Guo, Xueyi; Huang, Yucheng; Zheng, Chenghang

doi:10.1021/acs.est.5b06340

Cited by 63 publications

(21 citation statements)

References 27 publications

(41 reference statements)

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“…Along with the possible uptake of aerosols, mercury species may partake in nucleation, leading to a phase alteration, from a less condensed to a more condensed phase . Iron particles in the nanoregime have been proven to be excellent platforms to uptake many kinds of metal ions. , Liu et al demonstrated density functional theory (DFT) as well as conducted experimental studies on the mechanism of elemental mercury capture, in the presence of HCl on α-Fe 2 O 3 (001). Further experimental and theoretical works are yet to be done to understand the effect of a toxic metal, like mercury, on clay particles containing other metals.…”

Section: Introductionmentioning

confidence: 99%

Purely Inorganic Highly Efficient Ice Nucleating Particle

2018

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To evaluate the role of atmospheric heterogeneous reactions on the ice nucleation ability of airborne dust particles, we investigated the systematic study of ice nucleation microphysics with a suite of atmospherically relevant metals (10), halides (4), and oxyhalides (2). Within a minute, a kaolin–iron oxide composite (KaFe) showed efficient reactions with aqueous mercury salts. Among the different mercury salts tested, only HgCl 2 reacting with KaFe generated HgKaFe, a highly efficient ice nucleating particle (HEIN). When added to water, HgKaFe caused water to freeze at much warmer temperatures, within a narrow range of −6.6 to −4.7 °C. Using a suite of optical spectroscopy, mass spectrometry, and microscopy techniques, we performed various experiments to decipher the physical and chemical properties of surface and bulk. KaFe was identified as a mixture of different iron oxides, namely, goethite, hematite, magnetite, and ε-Fe 2 O 3 , with kaolin. In HgKaFe, HgCl 2 was reduced to Hg 2 Cl 2 and iron was predominantly in maghemite form. Reduction of Fe 2+ by NaBH 4 , followed by aerial oxidation, helped KaFe to be an exact precursor for the synthesis of HEIN HgKaFe. Kaolin served as a template for synthesizing iron oxide, opposing unwanted aggregation. No other metal or metal halide was found to have more efficient nucleating particles than HgCl 2 with KaFe composite. The chelation of Hg(II) hindered the formation of HEIN. This study is useful for investigating the role of morphology and how inorganic chemical reactions on the surface of dust change morphology and thus ice nucleation activity. The understanding of the fundamentals of what makes a particle to be a good ice nucleating particle is valuable to further understand and predict the amount and types of atmospheric ice nucleating particles.

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Section: Introductionmentioning

confidence: 99%

Purely Inorganic Highly Efficient Ice Nucleating Particle

2018

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“…The Mulliken charge analysis was performed to compute the charge transfer. The adsorption energy ( E ads ) is defined as the energy variation between the reactants and products of the adsorption process; the calculation formula is defined in eq …”

Section: Methodsmentioning

confidence: 99%

“…The adsorption energy (E ads ) is defined as the energy variation between the reactants and products of the adsorption process; the calculation formula is defined in eq 4. 34 =…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

In Situ-Formed Phenoxyl Radical on the CuO Surface Triggers Efficient Persulfate Activation for Phenol Degradation

Huang

Han

Xiang

et al. 2021

Environ. Sci. Technol.

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Transition-metal oxide (M x O y )-based persulfate (PDS) activation processes have demonstrated enormous potential for pollutant degradation in water purification. However, the mechanistic insight of PDS activation by a M x O y catalyst concerning the mediate role of the organic substrate remains obscure. Here, we demonstrated that the in situ-formed phenoxyl radical on the CuO surface can trigger efficient persulfate activation for phenol degradation. The formation of the phenoxyl radical was an innersphere process, which involved the successive steps of chemisorption through surface hydroxyl group substitution and the subsequent spontaneous electron transfer reaction from adsorbed phenol to CuO. The organic substrate phenol can be oxidized by the PDS molecule and surface-bound SO 4•− through the nonradical and free-radical pathways, respectively. Such a unique "half-radical" mechanism resulted in an extraordinarily high PDS utilization efficiency of 188.9%. More importantly, a general rule for phenoxyl radical formation was concluded; it can be formed in the cases of organic substrates with a Hammett constant σ + lower than −0.02 and metal ion of a 3d subshell between half-filled and fully filled. This study clarifies the mediate role of the organic substrate for interfacial PDS activation on M x O y and also gives new insights into the rational design of a highly efficient M x O y catalyst for selective phenolic/aniline pollutant degradation in wastewater.

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“…Pure spherical α-Fe 2 O 3 (Aladdin Chemistry Co., Ltd.) with a particle size of 30 nm and purity of 99.5% had been always used in our study. 7 Experimental Apparatus and Procedures. The experimental system diagram is pictured in Figure S1 of the Supporting Information (SI), which consists of the gas distribution system, mercury generator, reaction equipment, and online mercury measuring instrument.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Mechanisms of Elemental Mercury Transformation on α-Fe₂O₃(001) Surface from Experimental and Theoretical Study: Influences of HCl, O₂, and SO₂

Liu

Xue²,

Guo

et al. 2016

Environ. Sci. Technol.

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The reaction mechanisms of a mixture gas of HCl, O, and SO in Hg adsorption on α-FeO(001) surface are clarified by a group of adsorption experiments and theoretical calculations based on the density functional theory. The role of O in removing Hg is greatly influenced by the reaction temperature, meanwhile, the O atom coverage could affect the adsorption performance of Hg. The dissociated O competes with the active sites of Cl species on Fe surface at low temperature, however, at medium temperature HCl and O could simultaneously facilitate the Hg transformation. Combined with the theoretical calculations, the role of SO and the probable pathways in removing Hg are discussed. Lower concentration of SO as well as HCl could dissociate on α-FeO(001) surface, and the intermediates combine with gaseous Hg, forming mercury-sulfur, mercury-chlorine compounds, and so forth. In addition, the different concentrations of SO are also discussed, and the corresponding X-ray photoelectron spectroscopy analysis on contrasted samples is conducted to research the morphological characterization, providing a reliable basis for judging the probable pathways of Hg transformation.

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DFT and Experimental Study on the Mechanism of Elemental Mercury Capture in the Presence of HCl on α-Fe₂O₃(001)

Cited by 63 publications

References 27 publications

Purely Inorganic Highly Efficient Ice Nucleating Particle

Purely Inorganic Highly Efficient Ice Nucleating Particle

In Situ-Formed Phenoxyl Radical on the CuO Surface Triggers Efficient Persulfate Activation for Phenol Degradation

Mechanisms of Elemental Mercury Transformation on α-Fe₂O₃(001) Surface from Experimental and Theoretical Study: Influences of HCl, O₂, and SO₂

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DFT and Experimental Study on the Mechanism of Elemental Mercury Capture in the Presence of HCl on α-Fe2O3(001)

Cited by 63 publications

References 27 publications

Purely Inorganic Highly Efficient Ice Nucleating Particle

Purely Inorganic Highly Efficient Ice Nucleating Particle

In Situ-Formed Phenoxyl Radical on the CuO Surface Triggers Efficient Persulfate Activation for Phenol Degradation

Mechanisms of Elemental Mercury Transformation on α-Fe2O3(001) Surface from Experimental and Theoretical Study: Influences of HCl, O2, and SO2

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DFT and Experimental Study on the Mechanism of Elemental Mercury Capture in the Presence of HCl on α-Fe₂O₃(001)

Mechanisms of Elemental Mercury Transformation on α-Fe₂O₃(001) Surface from Experimental and Theoretical Study: Influences of HCl, O₂, and SO₂