Isosteric heat of water adsorption and desorption in homoionic alkaline-earth montmorillonites

Belhocine, M.; Haouzi, A.; Bassou, Ghaouti; Phou, Ty; Maurin, D.; Bantigniès, Jean-Louis; Henn, F.

doi:10.1016/j.chemphys.2017.11.012

Cited by 14 publications

(12 citation statements)

References 32 publications

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“…50,58,59 The isosteric heat is an important parameter that provides insights into the surface energetic heterogeneities and the fluid−fluid interactions. 105,106 The isosteric heats typically fall in the range of 10−15 kcal/mol (Figure 4). With increasing RH, water molecules are placed away from the surface which lowers the fluid−solid interactions and the isosteric heats.…”

Section: Simulation Detailsmentioning

confidence: 99%

Overview of the Adsorption and Transport Properties of Water, Ions, Carbon Dioxide, and Methane in Swelling Clays

Nair

Cui

Sun

2021

ACS Earth Space Chem.

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It is quite challenging to understand the details of the complex mechanisms involved in the swelling processes of clays such as montmorillonite as a function of relative humidity (RH), and the adsorption and transport processes of CO2 and CH4 in swelling clays. Here we present a review of the molecular simulation results for the swelling clay systems which not only compare well with the experimental data but also provide deep insights into the details of these mechanisms. The presence of CO2 and CH4 hardly affects the distribution and mobility of the interlayer water and ions in these systems. Under all conditions, the stable basal d-spacing was mainly determined by the type of counterion present in the interlayer region and the amount of water in each hydration state was almost independent of the RH and the layer charge. The uptake of CH4 in the 1W state of the Na-clay was much smaller compared to that of CO2. The adsorbate mobility generally increased with increasing hydration/RH because of the associated swelling of the interlayer region. Interestingly, the uptake of CO2 in the high-charge clay was dramatically decreased, and the mobility of CO2 in each hydration state was almost independent of the type of cation. The preferential adsorption of CO2 over CH4 plays an important role in the diffusion processes. Such an understanding is important for the successful mitigation of climate change via storage of anthropogenic CO2 in geological formations.

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Section: Simulation Detailsmentioning

confidence: 99%

Overview of the Adsorption and Transport Properties of Water, Ions, Carbon Dioxide, and Methane in Swelling Clays

Nair

Cui

Sun

2021

ACS Earth Space Chem.

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“…RH dependence of the isosteric heat of adsorption of water in (a) interlayers and on (b) external surfaces of the Arizona montmorillonite. The line represents the heat of vaporization of water 72. …”

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confidence: 99%

Layer Charge Effects on Adsorption and Diffusion of Water and Ions in Interlayers and on External Surfaces of Montmorillonite

Yang

Nair

Sun

2019

ACS Earth Space Chem.

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Molecular simulations using classical force fields were performed to study the adsorption and diffusion properties of water and ions in the high-charge (Arizonatype) montmorillonite clays with varying relative humidity (RH) at 298.15 K. The simulation results of basal distances derived from swelling free energy curves and of water uptake are in good agreement with experiments. Overall, the simulated self-diffusion coefficients of the interlayer species are in reasonable agreement with experiments and lower than those estimated for the external surfaces. Influence of the magnitude of the layer charge was studied by comparing these simulation results with those obtained for the low-charge (Wyoming-type) montmorillonite clays. Most importantly, these comparisons confirm the experimental finding that the high-charge clay generally shifts swelling transitions toward lower RH values. Therefore, the adsorption and dynamics of water and ions are significantly different in the low-and high-charge clays near the transition RH values. We find that the amount of water in an interlayer hydration state is mostly independent of the layer charge, probably due to steric reasons. In contrast, the externally adsorbed water content increases with increasing layer charge. Furthermore, the mobility of water and ions is generally lower in the high-charge montmorillonite than in the corresponding low-charge system. However, mobility of cations in the mesopores of high-charge montmorillonite is typically higher than that of the corresponding low-charge system which might be attributed to the presence of the tetrahedral substitutions in the later case.

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“…The potentiometric (sensitivity with respect to protons), viscosity, associative, and conformational behaviors are well known [2,3]. The bentonite is the most smectite clay commonly used due to its high permeability, high surface area, swelling behavior, adsorption, and high cation exchange capacity (CEC) [4]. Mt is used in various applications such as hydrogeology, civil engineering, petroleum engineering, environmental sciences and biological applications and catalysis [5].…”

Section: Introductionmentioning

confidence: 99%

“…They are also less expensive than the usual adsorbents such as activated carbon. Thus, they were the topic of a great number of studies, particularly when used for dyes retention [4], One of the most widely used adsorbents is activated carbon due to its high adsorption capacity for organic matter; however, it is expensive and difficult to regenerate. From this point of view, many nonconventional low-cost adsorbents have been proposed and developed for dye removal, e.g., bentonite [13].…”

Section: Introductionmentioning

confidence: 99%

Plasticizing Properties Improvement of Poly (4-Vinylpyridine)/Clay Composites: Effect of Composition and Clay Nature

Dergal

Lerari

Bachari

2021

Advances in Materials Science

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A significant number of investigations have been reported on the elaboration and characterization of Polymer/Clays composites, via different methods. In our work, new composites materials were successfully prepared by in-situ polymerization of 4-vinylpyridine (4VP), in presence of two different types of Algerian modified clays (Maghnia and Mostaganem), noted (BC) and (MC), respectively. Different percentage clays (1 wt%, 3 wt% and 5 wt%) have been used. The differential scanning calorimetry analysis reveals the variation of glass transition temperature (Tg) of the copolymer in the composite materials. We show a decrease glass transition temperature (Tg) from 147°C to 131°C for P4VP-BC and from 147°C to 124°C for P4VP-MC according to the increase percentage of clays. Thermogravimetric analysis (TGA) shows good stability of composite materials at high temperature. Fourier Transformed Infrared (FTIR), Scanning Electron Microscopy coupled with Energy dispersive X-Ray Spectroscopy (SEM-EDX) and 1H NMR spectroscopy are used to show the presence of the clays in the materials.

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Isosteric heat of water adsorption and desorption in homoionic alkaline-earth montmorillonites

Cited by 14 publications

References 32 publications

Overview of the Adsorption and Transport Properties of Water, Ions, Carbon Dioxide, and Methane in Swelling Clays

Overview of the Adsorption and Transport Properties of Water, Ions, Carbon Dioxide, and Methane in Swelling Clays

Layer Charge Effects on Adsorption and Diffusion of Water and Ions in Interlayers and on External Surfaces of Montmorillonite

Plasticizing Properties Improvement of Poly (4-Vinylpyridine)/Clay Composites: Effect of Composition and Clay Nature

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