NMR study of microscopic mechanism of water molecules diffusion in natrolite

Sapiga, A. V.; Sergeev, N. A.

doi:10.1016/j.ssnmr.2018.10.001

Cited by 2 publications

(3 citation statements)

References 20 publications

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“…Now we turn to the energy landscape interpretation, described by P (α, ε), Figure . As Q increased, the curves became equally broader, indicating that coupled long- and short-range motions lead to a non-Markovian diffusion process as previously observed in natrolite using NMR . On the other hand, at low Q values, similarly to observations for human acetylcholinesterase with and without inhibitor, , the lower energy energy barrier and narrower distributions observed for Mt can be related to the reduced EISF, higher dehydration temperature, but lower enthaply, i.e., this barrier behavior reflects that more electrons are shared elsewhere and not in the water molecule.…”

Section: Resultssupporting

confidence: 66%

“…As Q increased, the curves became equally broader, indicating that coupled long-and short-range motions lead to a non-Markovian diffusion process as previously observed in natrolite using NMR. 37 On the other hand, at low Q values, similarly to observations for human acetylcholinesterase with and without inhibitor, 19,20 the lower energy energy barrier and narrower distributions observed for Mt can be related to the reduced EISF, higher dehydration temperature, but lower enthaply, i.e., this barrier behavior reflects that more electrons are shared elsewhere and not in the water molecule. This can be explained by Mt polarizing the water molecules more in the interlayer than Ht, by making the ensemble of water molecules in the interlayer space less capable of hopping between the interlayer cation and the surface of its interlayer, hence not only distorting the water molecule tetragonal symmetry but also holding it longer.…”

Section: ■ Results and Discussionmentioning

confidence: 68%

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Assessing Diffusion Relaxation of Interlayer Water in Clay Minerals Using a Minimalist Three-Parameter Model

et al. 2021

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Using a minimal model approach for interpreting the intermediate scattering function, F(Q, t), to analyze quasi-elastic neutron scattering (QENS) data from interlayer water as a function of temperature in the 2D-layered clay minerals montmorillonite (Mt) and hectorite (Ht) a clear difference in behavior was observed. This was related to the polarization effect induced on the water molecules by both the exchangeable cation and surface charge within the interlayer. Although crucial for improving the wide range of industrial applications of clays as well as for explaining water uptake and retention by clays such information is neither obtained straightforwardly by other experimental methods nor fully accounted by molecular dynamics simulations. Furthermore, analysis of the evolution of the fitted parameters as a function of temperature shows that hydrogen atoms have a relaxation with a smaller average motional amplitude for Mt. Physically this can be explained as stronger hydrogen-bonding by water at the interlayer surfaces in Mt. These results allow for a novel and realistic description of these nanomaterials at the atomic scale, which is crucial for improving functional properties. These findings also prove that this new approach to modeling QENS captures subtle changes hidden in the spectra.

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Section: Resultssupporting

confidence: 66%

Section: ■ Results and Discussionmentioning

confidence: 68%

Assessing Diffusion Relaxation of Interlayer Water in Clay Minerals Using a Minimalist Three-Parameter Model

et al. 2021

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“…This structure demonstrates an organized distribution of silicon and aluminum, and its framework topology displays notable structural adaptability. It can expand, accommodating superhydrated structures, and undergo substantial contraction during dehydration [26], [45]. Natrolite is characterized as a small-pore zeolite with a needle-like crystal pattern [46], [48] and fibrous structure [30], [47] possessing a total pore volume of 22%.…”

Section: X-ray Diffraction (Xrd) Analysismentioning

confidence: 99%

Mitigation Measures of Swelling Characteristics in Alkali-Contaminated Red Earth using Fly Ash and GGBS Blends

Kumar Darapu,

Vindula

2023

IOP Conf. Ser.: Earth Environ. Sci.

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Alkali contamination induces swelling in the inherently non-swelling soils, resulting in heave severely damaging the sub and superstructures. Stabilization measures must be taken in vulnerable areas to prevent such colossal losses. Considerable research has been conducted regarding the swelling behavior of soils contaminated with alkalis and the impact of subsequent stabilization techniques utilizing different industrial byproducts and pozzolanic materials. However, there is a paucity of such studies on the Red Earth (RE) of the Visakhapatnam region. Furthermore, limited attention was given to the effects of extremely low concentrations of alkalis on the swelling behavior of soils. RE in the study area of the Visakhapatnam region predominantly consists of quartz, kaolinite, and hematite. In phase 1 of the experimental analysis, RE was contaminated with a highly dilute NaOH solution (0.05 N), and the resulting swell characteristics were investigated. A free swell of 10% was observed. One-dimensional standard oedometer tests revealed an equilibrium swelling of 5.6%, indicating significant potential for substantial heave and subsequent damage. X-ray diffraction (XRD) analysis revealed the formation of natrolite and analcime zeolites with a hollow structure, which caused the swell. Peaks of silicate minerals like paragonite and ussingite were also observed, indicating the dissolution of authigenic minerals and new precipitations even at lower concentrations of NaOH. In phase 2, swell tests were conducted on a mixture of contaminated red earth (50% w/w), fly ash (25% w/w), and ground granulated blast furnace slag (GGBS, 25% w/w), and it was observed that the swelling was completely arrested. XRD analysis unveiled that even though siliceous zeolites were formed, the development of chrysotile, attapulgite, tobermorite, and dicalcium silicate effectively inhibited the swelling with their pozzolanic behavior.

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NMR study of microscopic mechanism of water molecules diffusion in natrolite

Cited by 2 publications

References 20 publications

Assessing Diffusion Relaxation of Interlayer Water in Clay Minerals Using a Minimalist Three-Parameter Model

Assessing Diffusion Relaxation of Interlayer Water in Clay Minerals Using a Minimalist Three-Parameter Model

Mitigation Measures of Swelling Characteristics in Alkali-Contaminated Red Earth using Fly Ash and GGBS Blends

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