Ar+ ion bombardment dictates glycine adsorption on pyrite (1 0 0) surface: X-ray photoemission spectroscopy and DFT approach

Gálvez-Martínez, Santos; Escamilla‐Roa, Elizabeth; Zorzano, María Paz; Mateo‐Martí, Eva

doi:10.1016/j.apsusc.2020.147182

Cited by 9 publications

(6 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…46 During the XPS etching process, the high energy argon ion bombardment may generate substantial sulfur vacancies through a preferential sputtering mechanism. 48 However, after being cyclically oxidized in the presence of 0/10 mM NTA, the quantity of sulfur vacancy formed in the oxidized pyrite structure is significantly higher than that in the presence of 0.1 mM NTA and pristine pyrite (Figure S1c). In theory, changes in density and bond energies with composition may affect equilibrium sputtering yields for compounds; 49 therefore, it can be concluded that the cyclically oxidized pyrite in the presence of 0/10 mM NTA may have a more unstable internal structure.…”

Section: ■ Results and Discussionmentioning

confidence: 97%

“…However, as the etching depth increases to 50–200 nm, an obvious S(-II) peak at 161.2 eV occurs in each pyrite sample, which is assigned to sulfur vacancies in the pyrite structure . During the XPS etching process, the high energy argon ion bombardment may generate substantial sulfur vacancies through a preferential sputtering mechanism . However, after being cyclically oxidized in the presence of 0/10 mM NTA, the quantity of sulfur vacancy formed in the oxidized pyrite structure is significantly higher than that in the presence of 0.1 mM NTA and pristine pyrite (Figure S1c).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Redox Behavior of Secondary Solid Iron Species and the Corresponding Effects on Hydroxyl Radical Generation during the Pyrite Oxidation Process

Zhao

Peng

et al. 2022

Environ. Sci. Technol.

View full text Add to dashboard Cite

During the pyrite oxidation process, aqueous ferrous/ferric ions (Fe 2+ /Fe 3+ ), as well as surface-adsorbed Fe 2+ /Fe 3+ , have been widely recognized to dominate hydroxyl radical ( • OH) generation, while this study reveals that the secondary solid iron species also play nonnegligible roles. Based on the different forms and the presence of sites, the secondary solid iron species were classified as Fe coat (iron-containing coating on the pyrite surface) and Fe dep (ex situ-deposited iron (oxyhydr)oxide that is not in contact with pyrite). Instead of participating in building a stubborn passivation layer on the pyrite surface, Fe coat is easy to fall off from the pyrite surface as the oxidation of pyrite deepens, while large fractions of Fe dep and Fe coat are found to be extractable with nitrilotriacetic acid (NTA). Achieved by cyclically oxidizing pyrite within different NTA levels (0/0.1/10 mM), Fe coat and Fe dep were proved to have distinct redox behavior during the pyrite oxidation process. Amorphous Fe dep , originated from the hydrolyzation of dissolved Fe 3+ , accelerates the nonradical decay of hydrogen peroxide (H 2 O 2 ); as a result, the accumulation of Fe dep always decreases the • OH production during the pyrite oxidation process. However, part of Fe dep adsorbs on the pyrite surface through electrostatic attraction and converts into Fe coat . The electron conduction between Fe coat and pyrite was verified, which accelerates the oxidative dissolution of pyrite, produces reactive Fe(II), and therefore favors • OH generation. This study improves our understanding of the redox behavior of pyrite in complex media such as natural processes and practical engineering systems.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Redox Behavior of Secondary Solid Iron Species and the Corresponding Effects on Hydroxyl Radical Generation during the Pyrite Oxidation Process

Zhao

Peng

et al. 2022

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…This is because there is no interaction between the S III atom and the atoms on the ideal surface. DFT calculation results in the literature 13 also show that S III atoms are easily detached from the surface.…”

Section: Reconstruction Of Surface Stabilitymentioning

confidence: 79%

“…Later researchers used argon-ions to bombard the surface of FeS 2 , and S atoms on the surface missing after bombardment, resulting in the surface Fe 2+ -Fe 3+ . 9,13 At the same time, Fe atoms with missing coordination combine easily with OH. 14 During the acid leaching process, a passivation layer is formed on the surface of chalcopyrite, and XPS detection analysis reveals the presence of S 4 2À species in the passivation layer.…”

Section: Introductionmentioning

confidence: 99%

Atomic reconstruction and oxygen adsorption behavior of the pyrite (100) surface: a DFT study

Chen

Zhou

et al. 2023

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…The Ar + bombardment causes substantial disordering of crystal and electronic structures, reduction of some elements, and so on, so the information on the chemical state of atoms will be lost; moreover, elemental composition can change under the ion beam, too. For example, ion bombardment of pyrite results in preferential removal of S atoms, producing disordered layer with high-spin Fe 2+ /Fe 3+ cations and sulfide anions instead of singlet ferrous iron and disulfide groups [126,127]. Nevertheless, the Ar + bombardment is often employed for depth-profiling down to about 100 nm, although for rough and inhomogeneous surfaces of real, oxidized sulfide minerals it provides semi-quantitative concentration distributions at best.…”

Section: Ion Sputtering and Depth Profilingmentioning

confidence: 99%

X-ray Photoelectron Spectroscopy in Mineral Processing Studies

Mikhlin

2020

Applied Sciences

View full text Add to dashboard Cite

Surface phenomena play the crucial role in the behavior of sulfide minerals in mineral processing of base and precious metal ores, including flotation, leaching, and environmental concerns. X-ray photoelectron spectroscopy (XPS) is the main experimental technique for surface characterization at present. However, there exist a number of problems related with complex composition of natural mineral systems, and instability of surface species and mineral/aqueous phase interfaces in the spectrometer vacuum. This overview describes contemporary XPS methods in terms of categorization and quantitative analysis of oxidation products, adsorbates and non-stoichiometric layers of sulfide phases, depth and lateral spatial resolution for minerals and ores under conditions related to mineral processing and hydrometallurgy. Specific practices allowing to preserve volatile species, e.g., elemental sulfur, polysulfide anions and flotation collectors, as well as solid/liquid interfaces are surveyed; in particular, the prospects of ambient pressure XPS and cryo-XPS of fast-frozen wet mineral pastes are discussed. It is also emphasized that further insights into the surface characteristics of individual minerals in technological slurries need new protocols of sample preparation in conjunction with high spatial resolution photoelectron spectroscopy that is still unavailable or unutilized in practice.

show abstract

Ar+ ion bombardment dictates glycine adsorption on pyrite (1 0 0) surface: X-ray photoemission spectroscopy and DFT approach

Cited by 9 publications

References 40 publications

Redox Behavior of Secondary Solid Iron Species and the Corresponding Effects on Hydroxyl Radical Generation during the Pyrite Oxidation Process

Redox Behavior of Secondary Solid Iron Species and the Corresponding Effects on Hydroxyl Radical Generation during the Pyrite Oxidation Process

Atomic reconstruction and oxygen adsorption behavior of the pyrite (100) surface: a DFT study

X-ray Photoelectron Spectroscopy in Mineral Processing Studies

Contact Info

Product

Resources

About