Oxidation mechanism of the arsenopyrite surface by oxygen with and without water: Experimental and theoretical analysis

Chen, Manjiao; Zhang, Zhengfu; Hu, Xinjun; Tian, Jianping; Wang, Jingsong; Wan, Rundong; Zhou, Xiaohai; Shen, Peilun; Liu, Dianwen

doi:10.1016/j.apsusc.2021.151574

Cited by 17 publications

(24 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The adsorption of water molecules on the lollingite (101) surface was more inclined to the physical adsorption, because the adsorption energy is close to the positive values. In striking contrast, the adsorption distance of water molecules is far from the surface atoms, and the atomic interaction is relatively weak . The most stable adsorption configuration is the Fe site, with an adsorption energy of −29.477 kJ/mol.…”

Section: Resultsmentioning

confidence: 96%

“…Additionally, as has been demonstrated in the literature, the oxygen adsorption arrangement at the bridge sites of both Fe and As was more stable. 22,42 Due to the arsenic atom's strong impact on the electrical structure on the surface of pyrite, arsenopyrite and lollingite had significantly higher adsorption energies compared to the most stable pyrite adsorption sites. This discrepancy could be attributed to the valence electron configurations and the various methodologies.…”

Section: Adsorption Of Isolated O 2 Molecules and Isolated H 2 O Mole...mentioning

confidence: 99%

“…In striking contrast, the adsorption distance of water molecules is far from the surface atoms, and the atomic interaction is relatively weak. 42 The most stable adsorption configuration is the Fe site, with an adsorption energy of −29.477 kJ/mol. The distance between the oxygen atom of the H 2 O molecule and the Fe atom on the surface of the lollingite was 2.216 Å.…”

Section: Adsorption Of Isolated O 2 Molecules and Isolated H 2 O Mole...mentioning

confidence: 99%

“…Moreover, the reaction energy barrier of arsenopyrite in this step was 32.99 and 46.65 kJ/mol, respectively, indicating that the water molecules slightly hinder this reaction step and increase the reaction energy barrier. 42 According to the calculation results that have been reported in the literature, the incorporation of water will inevitably raise the energy barrier for the formation of the Fe−O−As−O−Fe bridge oxygen structure. 38 The second stage includes the control steps of arsenopyrite, owing to the fact that the dissociation of H 2 O molecules was the rate-determining factor.…”

Section: Oxidation Behavior Of Omentioning

confidence: 99%

“…34 Therefore, the underlying physical properties of FeAsS and FeS 2 are different, and more active arsenic sites can be found on FeAsS surfaces. 42 Compared with FeAsS and FeS 2 , FeAs 2 also exhibits different properties without sulfur atoms. The combination modes of arsenic and iron are different compared to arsenopyrite, and differences in the oxidative adsorption process of H 2 O + O 2 can be detected since the reaction process depends on the bulk structure, electronegativity of the constituent atoms, and the favorable redox reaction energetics.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

et al. 2023

View full text Add to dashboard Cite

Lollingite (FeAs2) is considered an arsenic-bearing mineral that is oxidized faster than arsenopyrite. The geometric configuration, chemical valence bond, and microscopic reaction of the oxidation on the surface of lollingite were systematically studied, which are of great significance for understanding the mechanism of oxidative dissolution. X-ray photoelectron spectroscopy (XPS) measurements and density functional theory (DFT) calculations were carried out to characterize the (101) surface oxidation process of lollingite under the O2/O2 + H2O conditions. XPS results confirmed that the participation of water molecules can promote the formation of abundant OH structures on the surface of lollingite, while the relative concentration of O, As(III), and Fe(III) increased. Moreover, the DFT results demonstrated that the (101) As-terminal plane of FeAs2 was the most stable surface with the lowest surface energy. H2O molecules were physically adsorbed onto the Fe atoms of the lollingite surface, while oxygen molecules can readily be adsorbed on the Fe–As2 site by chemical adsorption processes. The oxidation process of the lollingite surface with water includes the following mechanisms: adsorption, dissociation, formation of the hydrogen bond, and desorption. The dissociation of the H2O molecule into OH and H led to the hydroxylation of both Fe and As atoms and the formation of hydrogen bonding. The participation of H2O molecules can also reduce the reaction energy barrier and accelerate the oxidation reaction of the lollingite surface, especially as far as the water dissociation and formation of hydrogen bonds are concerned. According to PDOS data, there is considerable hybridization between the d orbitals of bonded Fe atoms and the p orbitals of O atoms, as well as between the p orbitals of bonded As atoms and the p orbitals of O atoms. Due to a strong propensity for orbital hybridization and bonding between the s orbitals of the H atoms in H2O molecules and the p orbitals of the O atoms on the (101) surface, water molecules have the ability to speed up the oxidation on the surface.

show abstract

Section: Resultsmentioning

confidence: 96%

Section: Adsorption Of Isolated O 2 Molecules and Isolated H 2 O Mole...mentioning

confidence: 99%

Section: Adsorption Of Isolated O 2 Molecules and Isolated H 2 O Mole...mentioning

confidence: 99%

Section: Oxidation Behavior Of Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

et al. 2023

View full text Add to dashboard Cite

show abstract

First‐principles study on the effect of arsenic impurity on oxidation of pyrite surfaces

Fu,

Li,

Chen

et al. 2023

Int J of Quantum Chemistry

View full text Add to dashboard Cite

Arsenic (As) frequently exists in pyrite (FeS2) in the form of impurities. The oxidation behavior of As in FeS2 is important in environmental science, mineral processing, and other related fields. The adsorption behaviors of H2O and O2 molecules on the As‐bearing pyrite (100) surface (AsFeS2(100)) are studied using the density functional theory (DFT). The results show that As prefers the S site on the pyrite (100) surface (FeS2(100)). In the absence of O2, an isolated H2O molecule does not dissociate when adsorbed at an iron (Fe) site and is repelled at an As site. Furthermore, the surface area around the As atoms exhibits a hydrophobic behavior. Adsorption energy analysis reveals that the presence of As atoms is unfavorable for the adsorption of H2O molecules on the pure FeS2 surface, and that the adsorption of H2O molecules on the AsFeS2(100) is physical adsorption. In the absence of H2O, it is suggested that the O2 molecule easily dissociates on both the pure FeS2(100) and AsFeS2(100). The adsorption of O2 on the As‐bearing surface is weaker than that on the pure FeS2(100). For the co‐adsorption of H2O and O2, the adsorption energy on the As‐bearing surface is more negative than that on the pure surface. This indicates that the presence of As promotes surface oxidation. Additionally, two OH and O (AsO or SO) or O (FeO) species are formed on the surface of pyrite when the H2O molecule is dissociated.

show abstract

Eco-utilization of steel slag: Preparation of Fe-based calcium silicate hydrate and its application in As(V) removal

Pan

et al. 2022

Applied Surface Science

View full text Add to dashboard Cite

Oxidation mechanism of the arsenopyrite surface by oxygen with and without water: Experimental and theoretical analysis

Cited by 17 publications

References 57 publications

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

First‐principles study on the effect of arsenic impurity on oxidation of pyrite surfaces

Eco-utilization of steel slag: Preparation of Fe-based calcium silicate hydrate and its application in As(V) removal

Contact Info

Product

Resources

About

Oxidation mechanism of the arsenopyrite surface by oxygen with and without water: Experimental and theoretical analysis

Cited by 17 publications

References 57 publications

Impact of H2O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Impact of H2O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

First‐principles study on the effect of arsenic impurity on oxidation of pyrite surfaces

Eco-utilization of steel slag: Preparation of Fe-based calcium silicate hydrate and its application in As(V) removal

Contact Info

Product

Resources

About

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses