Na+ as a probe to structural investigation of dehydrated smectites using NMR spectra calculated by DFT

Fonseca, Carla G.; Carvalho, Gustavo Senra Gonçalves de; Diniz, Renata; Leitão, Alexandre A.

doi:10.1016/j.clay.2016.03.001

Cited by 18 publications

(17 citation statements)

References 41 publications

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“…On the other hand, the V zz obtained values are not far from the experimental data. For Mg, the calculated δ chem using Ref [37] resulted higher than that observed in Ref [26].…”

Section: B-hyperfine Characterizationcontrasting

confidence: 60%

“…Regarding 23 Na, the comparison of the calculated δ chem with the experimental one becomes difficult due to the strong dependence on the A and B empirical parameters selection. Specially, the B parameter presents strong differences between the data form Ref [64] and Ref [37], and this difference particularly affects the results for chemical shifts near zero, as in this case.…”

Section: B-hyperfine Characterizationmentioning

confidence: 87%

“…Between the experimental techniques used to enlighten the mechanisms involved in metal/clay complexation, Nuclear Magnetic Resonance (NMR) became an important tool due to its high sensitivity to the local environment of the atoms and the chemical bonds. Clay layers were previously studied with this technique using 25 Mg, 27 Al and 29 Si as probe atoms [25][26][27][28][29][30][31][32] , whereas for the clay interlayer and swelling behavior, the studies were performed using 113 Cd, 133 Cs, and 23 Na probes [33][34][35][36][37] .…”

mentioning

confidence: 99%

“…Experimental and calculated chemical shift, V zz and η. a using coefficients from Ref[64]. b using coefficients from Ref[37]. c using coefficients from Ref[63].…”

mentioning

confidence: 99%

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Experimental and theoretical study of Co sorption in clay montmorillonites

Rebaza

Montes

Taylor

et al. 2018

Mater. Res. Express

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Montmorillonite (MMT) clays are 2:1 layered structures which in natural state may allocate different hydrated cations such as M-nH2O (M= Na, Ca, Fe, etc.) in its interlayer space. Depending on the capability for ion sorption, these materials are interesting for environmental remediation. In this work we experimentally study the Co sorption in a natural Na-MMT using UV-visible spectrometry and XRD on semi-oriented samples, and then analyze the sorption ability of this clay by means of ab initio calculation performed on pristine MMT. The structural properties of Na-MMT and Co-adsorbed MMT, and the hyperfine parameters at different atomic sites were analyzed and compared with the experimental ones for the first, and for the case of the hyperfine parameters, presented for the first time for the last. The theoretical predictions based on total energy considerations confirm that Co incorporation replacing Na is energetically favorable. Also, the basal spacing d 001 experimentally obtained is well reproduced. 1-Introduction From the beginning of the industrial revolution, environmental pollution by heavy metals appeared as a direct consequence, and its reversal represents a challenge for modern life. In this scenario pollutants generation and the deposition controls constitute a very important topic due to the negative effects that these elements could cause both on the human health and the environmental quality. Among the mechanisms used for heavy metal removal from effluents, ion exchange allows the use of low cost and environmental friendly materials, like clay minerals and its derivatives (modified clays that enhance the sorption process of the sorbent material) 1-3. Among them, Montmorillonite (MMT), a 2:1 clay mineral, is one of the most promising candidates for decontamination and disposal of wastewater with high-level heavy metal cation content, due to its relatively high specific area and cation exchange capacity 4, 5 .

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“…On the other hand, the V zz obtained values are not far from the experimental data. For Mg, the calculated δ chem using Ref [37] resulted higher than that observed in Ref [26].…”

Section: B-hyperfine Characterizationcontrasting

confidence: 60%

Section: B-hyperfine Characterizationmentioning

confidence: 87%

mentioning

confidence: 99%

“…Experimental and calculated chemical shift, V zz and η. a using coefficients from Ref[64]. b using coefficients from Ref[37]. c using coefficients from Ref[63].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Experimental and theoretical study of Co sorption in clay montmorillonites

Rebaza

Montes

Taylor

et al. 2018

Mater. Res. Express

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“…DFT based studies have shown to be a valuable method for describing the structures and dehydration of the Mt-Na + compound. 32 Such studies reinforce that the dehydrated montmorillonite is potential for the synthesis of, for example, nanocomposites based on hydrophobic polymers such as PMMA, which exhibits low polymerization in the presence of water. 33…”

Section: Introductionmentioning

confidence: 61%

Structural and Electronic Properties of Iron-Doped Sodium Montmorillonite Clays: A First-Principles DFT Study

et al. 2019

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First-principles calculations done via density functional theory were used to study the structural and electronic properties of sodium montmorillonite clay (Mt-Na+) of general formula MxAl3Si8O24H4Na·nH2O (Mx: Mg or Fe). The final position of the interlamellar sodium atom is found to be close to the oxygen atoms located on the upper surface of silica. Following Fe-Mt-Na+ system relaxation, with subsequent analysis of magnetic moment and magnetic states, the electroneutrality of the system established that both Fe2+ and Fe3+ oxidation states are possible to occur. The Mg2+-Mt-Na+ material shows a band gap energy greater than that of Fe2+-Mt-Na+ when iron is in the octahedral site. It is found that the valence-band maximum and the conduction-band minimum of iron-doped montmorillonite are both at the Γ-point, while it is at V → Γ for magnesium-doped montmorillonite. The calculated band gap from hybrid functional (HSE06) of Fe2+-Mt-Na+ is equal to 4.3 eV, exhibiting good agreement with experimental results obtained from ultraviolet–visible spectroscopy of the natural Mt-Na+ (Cloisite-Na+).

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Computational modeling of nanoclays

Scholtzová

2020

Clay Nanoparticles

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Na+ as a probe to structural investigation of dehydrated smectites using NMR spectra calculated by DFT

Cited by 18 publications

References 41 publications

Experimental and theoretical study of Co sorption in clay montmorillonites

Experimental and theoretical study of Co sorption in clay montmorillonites

Structural and Electronic Properties of Iron-Doped Sodium Montmorillonite Clays: A First-Principles DFT Study

Computational modeling of nanoclays

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