ELECTRONIC STRUCTURES AND THE STABILITY OF <font>MgO</font> SURFACE: DENSITY FUNCTIONAL STUDY

Zhang, Dian-Na; Zhao, Li‐Dong; Wang, Jiafu; Li, Yan-Li

doi:10.1142/s0218625x15500377

Cited by 15 publications

(11 citation statements)

References 38 publications

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“…The as obtained heterostructured composite with high surface area would be suitable for the adsorption of heavy metal ions. The computed lattice parameters are found to deviate from the bulk compounds, i.e., 3.6600 Å and 9.7600 Å for anatase TiO 2 [29], 4.2110 Å for MgO [30], and 6.7824 Å for g-C 3 N 4 [31]. This can be associated with the occurrence of the dissolution of Mg ions within TiO 2 host lattice by occupying Ti ionic sites followed by its expansion since Mg 2+ (0.72 Å) has a larger ionic radius compared to that of Ti 4+ (0.61 Å).…”

Section: Resultsmentioning

confidence: 89%

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO₂@g‐C₃N₄

Modwi

Ismail

Idriss

et al. 2022

Journal of Nanomaterials

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MgO@TiO2@g-C3N4 heteronanostructure was synthesized using a simple ultrasonication technique and assessed potentially to remove Cd (II) from aqueous environments. X-ray diffraction analysis confirms composite formation with mean crystallite size in the range of 4-17 nm while transmission electron microscopy analysis reveals nanosheet-like nanoparticles with the homogeneous elemental distribution. N2 adsorption-desorption measurements indicate the formation of a mesoporous structure with a BET surface area of about 107 m2/g. Fourier-transformed infrared elucidates the presence of O–H, amino groups, triazine, Mg–O, and Ti–O vibrations modes. At the same time, X-ray photoelectron spectroscopy analysis manifests the presence of Mg, O, N, Ti, and C elements. For aqueous Cd (II) ions, the MgO@TiO2@g-C3N4 nanostructure displays a superior adsorption efficiency, reaching 99.94% Cd (II) elimination with an optimum adsorption capacity of 515.86 mg/g in a short duration of 16 min. This study demonstrates the capability of using the MgO@TiO2@g-C3N4 nanostructure as an efficient and reusable adsorbent for the uptake of Cd (II) ions in wastewater treatment and potentially for the removal of other heavy metal ions.

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Section: Resultsmentioning

confidence: 89%

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO₂@g‐C₃N₄

Modwi

Ismail

Idriss

et al. 2022

Journal of Nanomaterials

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“…The O‐terminated CeO 2 (111) surface exposes three‐fold coordinated O atoms with seven‐fold coordinated Ce atoms (O 3c , Ce 7c , respectively) [41] . MgO (100) surface is a flat terrace exposing O and Mg atoms with five‐fold coordination each [31b,42] . β‐SiO 2 (100) cleaved bulk contains three‐fold Si coordination (Si 3c ) and one‐coordinated non‐bridging O atoms (O 1c ) at the topmost layer.…”

Section: Resultsmentioning

confidence: 99%

“…The bulk and surfaces electronic structure main differences are related to the oxygen electron dangling bonds at the surface, which causes a decrease in the bandgap's size (see Table S2) [31b,50] . Although the DOS analysis gives information about the characteristics of the material, further research needs to be done to clarify the relationship between their acid/base properties and the compounds in HDO processes.…”

Section: Resultsmentioning

confidence: 99%

“… [41] MgO (100) surface is a flat terrace exposing O and Mg atoms with five‐fold coordination each. [ 31b , 42 ] β‐SiO 2 (100) cleaved bulk contains three‐fold Si coordination (Si 3c ) and one‐coordinated non‐bridging O atoms (O 1c ) at the topmost layer. Finally, a‐TiO 2 (101) surface has a five‐fold coordination Ti atoms (Ti 5c ) and two‐ and three‐fold coordinated O atoms (O 2c and O 3c ).…”

Section: Resultsmentioning

confidence: 99%

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The Effect of Pristine and Hydroxylated Oxide Surfaces on the Guaiacol HDO Process: A DFT Study

Morteo-Flores

Roldán

2021

ChemPhysChem

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The acid-base character of oxide supports is crucial for catalytic reactions. In this work, the acid-base properties of five oxide surfaces common in heterogeneous catalysis were investigated and related to their interaction with monolignol compounds derived from lignin. We have used density functional theory simulations also to understand the role of the surfaces' hydroxylation state. The results show that moderate hydroxyl coverage on the amphoteric γ-Al 2 O 3 (110) slightly strengthens the oxy-compounds' adsorption due to an increase in Lewis acidity. Similarly, low hydroxyl coverage on the reducible TiO 2 (101) enlarges its adsorption capacity by up to 42 % compared with its clean surface. The higher affinity is attributed to the more favourable interaction between the surface-OH groups and the aromatic rings. Overall, the results indicate that hydroxyl coverage enhances the amphoteric and reducible adsorption capacity towards aromatic species.

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“…As a result, the electronic orbit of Hg varies . To understand the stability of different surface structures based on the electronic nature of materials, the density of states and the band structures are often calculated. , The software of ELK was utilized to compare the band structure of Hg 0 vapor with and without the EMF so as to further understand the energy level splitting of Hg. As shown in Figure b, the band structures are plotted at all the points in the G–Z line.…”

Section: Effect Of External Fields and Ultraviolet Lightmentioning

confidence: 99%

Mercury Removal Based on Adsorption and Oxidation by Fly Ash: A Review

Liu

Zhao

et al. 2020

Energy Fuels

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Mercury (Hg), in particular elemental mercury (Hg0) captured from coal-fired power plants, has attracted much attention because of its severe harm to human health and environment. Hg0 can be removed using the technology of adsorbent injection, and one of the promising adsorbents is fly ash. To evaluate the effect of complex multifactors of fly ash on Hg0 removal performance, this review summarizes, analyzes, and evaluates the quantitative effects of fly ash compositions, physical parameters, flue gas components, and modification reagents. The effects of electric field (EF), magnetic field (MF), and ultraviolet (UV) light on Hg0 removal using fly ash are also introduced. Unburned carbon (UBC) and Fe2O3 are two reactive components in fly ash for Hg0 oxidation. Physical parameters including higher specific surface area, larger total pore volume, and wider distribution of pores with well-developed micropores are beneficial for Hg0 retention, and no consistent relationship between particle size and Hg0 retention using fly ash has been obtained. While gas phase components including HCl, NO, and O2 promote the removal of Hg0 using fly ash, no agreement about the effects of SO2 and H2O vapor on Hg0 removal has been reached. The promotion of halogen-modified fly ash on Hg0 removal may be explained by the Langmuir–Hinshelwood mechanism, the Mars–Maessen mechanism, as well as the Eley–Ridel mechanism. The contribution of metal-modified fly ash to Hg0 removal is attributed to the oxidation ability of metal oxides as well as metal positive ions. EF, MF, and UV light enhance the oxidation of Hg0 using fly ash to different degrees. The promotion of EF may be attributed to the formation of more Cl, O, and OH radicals by a series of electron-induced reactions. The enhancement of MF is simultaneously attributed to the energy-level splitting of Hg0 as well as the magnetochemistry effect of magnetic materials in fly ash. The function of fly ash on the photocatalytic oxidation of Hg0 under the UV light has been verified, while relevant studies are still limited. More studies are still needed on the relationship between surface functional groups and carbon types, the control of Hg0 secondary emission from the spent fly ash, the development of fly ash-based products, the compromise between fly ash modification cost and Hg0 removal efficiency, and the effective and economical coremoval of Hg0, NO x , and SO x using fly ash. In particular, the promotional effects of EF, MF, and UV light on Hg0 removal necessitate extensive studies on their underlining mechanisms. This review resolves the existing controversies on the Hg0 removal mechanism and promotes the development of fly ash on Hg0 removal from coal combustion.

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ELECTRONIC STRUCTURES AND THE STABILITY OF MgO SURFACE: DENSITY FUNCTIONAL STUDY

Cited by 15 publications

References 38 publications

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO₂@g‐C₃N₄

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO₂@g‐C₃N₄

The Effect of Pristine and Hydroxylated Oxide Surfaces on the Guaiacol HDO Process: A DFT Study

Mercury Removal Based on Adsorption and Oxidation by Fly Ash: A Review

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ELECTRONIC STRUCTURES AND THE STABILITY OF MgO SURFACE: DENSITY FUNCTIONAL STUDY

Cited by 15 publications

References 38 publications

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO2@g‐C3N4

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO2@g‐C3N4

The Effect of Pristine and Hydroxylated Oxide Surfaces on the Guaiacol HDO Process: A DFT Study

Mercury Removal Based on Adsorption and Oxidation by Fly Ash: A Review

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Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO₂@g‐C₃N₄

Efficient Removal of Cd (II) from Aquatic Media by Heteronanostructure MgO@TiO₂@g‐C₃N₄