Current Status and Perspectives of the Thermomolecular Engine Developing

Popyk, Artem; Ерошенко, В. А.

doi:10.5541/ijot.509

Cited by 9 publications

(9 citation statements)

References 15 publications

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“…One of the promising technologies of mechanical energy absorption, storage, and generation is based on forced penetration of a nonwetting liquid in porous solids, − where the energy of applied pressure is converted into the energy of the solid–liquid interface. First “porous solid/nonwetting liquid” systems – also called heterogeneous lyophobic systems (HLS) – were developed by Eroshenko and co-workers on the basis of porous silica. ,,, Since 2001, pure-silica zeolites (zeosils) have been proposed for this kind of application .…”

Section: Introductionmentioning

confidence: 99%

Intrusion–Extrusion of Electrolyte Aqueous Solutions in Pure Silica Chabazite by in Situ High Pressure Synchrotron X-ray Powder Diffraction

et al. 2018

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Structural investigation of the high pressure intrusion/extrusion of different electrolyte aqueous solutions (NaCl, NaBr and CaCl2) with different concentrations (2M and 3M) in a pure-silica chabazite was carried out. In situ synchrotron X-ray powder diffraction experiments were performed in the pressure range of 0.12 -2.6 GPa and upon pressure release, in order to unravel the interactions among intruded species and host material. The energetic performance of the systems were determined by porosimetric studies. Results show that cation in the salt seems to influence the intrusion-extrusion pressures, whereas the structural evolutions, undergone by the systems upon pressure-induced intrusion, are essentially independent on the nature of the penetrating media.Moreover, the initial electrolyte concentration seems to influence only the value of the intrusion pressure, but neither the amount nor the interaction mode of the intruded species. Both water and salt molecules enter the pores and the penetration of comparable extra-framework volumes occurs at similar pressure values. However, the composition of intruded species is different from that of initial solution and depends on applied pressure that reinforces the hypothesis on ion desolvation under penetration into the pores. After pressure release, pure-silica chabazite intruded by NaCl and NaBr aqueous solutions does not recover the initial cell volume and partially retains the intruded extra-framework species. On the contrary, the zeosil intruded by CaCl2 recovers the original cell parameters. These differences have been structurally interpreted on the basis of the electrolyte/zeolite interactions. Interestingly, the extrusion behavior results to be mainly determined by the interactions of the anion with silanol defects of chabazite framework, rather than by the coordination bonds of the cation with the framework oxygen atoms.

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Section: Introductionmentioning

confidence: 99%

Intrusion–Extrusion of Electrolyte Aqueous Solutions in Pure Silica Chabazite by in Situ High Pressure Synchrotron X-ray Powder Diffraction

et al. 2018

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“…Due to the rapid decrease of intrusion pressure with temperature increase [15], the systems (porous solid-non-wetting liquid) with spring behavior can also be used for the generation of mechanical energy from low potential ("waste") heat. In this case, the system works as a heat engine (so-called thermomolecular engine) with a specific thermodynamic cycle and becomes a source of renewable energy [16][17][18][19]. HLS can also be used for other particular applications, such as volume-memory materials [20] or as materials with extremely high negative expansion coefficient [21].…”

Section: Potential Applications Of Heterogeneous Lyophobic Systemsmentioning

confidence: 99%

Energetic Performance of Pure Silica Zeolites under High-Pressure Intrusion of LiCl Aqueous Solutions: An Overview

et al. 2020

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An overview of all the studies on high-pressure intrusion—extrusion of LiCl aqueous solutions in hydrophobic pure silica zeolites (zeosils) for absorption and storage of mechanical energy is presented. Operational principles of heterogeneous lyophobic systems and their possible applications in the domains of mechanical energy storage, absorption, and generation are described. The intrusion of LiCl aqueous solutions instead of water allows to considerably increase energetic performance of zeosil-based systems by a strong rise of intrusion pressure. The intrusion pressure increases with the salt concentration and depends considerably on zeosil framework. In the case of channel-type zeosils, it rises with the decrease of pore opening diameter, whereas for cage-type ones, no clear trend is observed. A relative increase of intrusion pressure in comparison with water is particularly strong for the zeosils with narrow pore openings. The use of highly concentrated LiCl aqueous solutions instead of water can lead to a change of system behavior. This effect seems to be related to a lower formation of silanol defects under intrusion of solvated ions and a weaker interaction of the ions with silanol groups of zeosil framework. The influence of zeosil nanostructure on LiCl aqueous solutions intrusion–extrusion is also discussed.

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“…Such intrusion/extrusion experiments have been performed in the past mainly with water for investigating the effective water contact angle for highly hydrophobized mesoporous silica materials 35,[44][45][46] . Furthermore, in order to assess the hydrophilicity/hydrophobicity of a pore surface, a hydrophobicity index was suggested which can be determined by studying the competitive adsorption of water and toluene or water and methylcyclohexane vapor mixtures 47,48 .…”

Section: Introductionmentioning

confidence: 99%

Quantitative Assessment of Hydrophilicity/Hydrophobicity in Mesoporous Silica by combining Adsorption, Liquid Intrusion and solid-state NMR spectroscopy

Collados

Huber

Söllner

et al. 2023

Preprint

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We have developed a comprehensive strategy for assessing the surface chemistry of nanoporous materials by combining advanced adsorption studies, novel liquid intrusion techniques and solid-state NMR spectroscopy. For this we have chosen a well-defined system of model materials, i.e., the highly ordered mesoporous silica molecular sieve SBA-15 in its pristine state, and functionalized with different amounts of trimethylsilyl groups. For an absolute quantification of the trimethylsilyl group density, quantitative 1H solid-state NMR spectroscopy under Magic Angle Spinning was employed. 1H two-dimensional single quantum double quantum MAS NMR spectra reveal an intimate mixture of TMS and residual OH groups on the surface. A full textural characterization of the materials was obtained by high-resolution argon at 87 K adsorption, coupled with the application of dedicated methods based on non-local-density functional theory. Based on the known texture of the model materials, we developed a method allowing one to determine the effective contact angle of water adsorbed on the pore surfaces, constituting a powerful parameter for the characterization of the surface chemistry inside porous materials. The surface chemistry was found to vary from a hydrophilic to a hydrophobic as the TMS functionalization content was increased, leading to contact angles from 0 ° (complete wetting) to 120 ° (non-wetting). For wetting and partial wetting surfaces, pore condensation of water is observed at pressures P smaller than the bulk saturation pressure P0 (i.e., at P/P0 < 1), the contact angle was determined from the water sorption isotherms by applying the modified Kelvin equation on the desorption branch of the observed hysteresis loop (which reflects here the thermodynamic liquid-vapour transition). However, on non- wetting surfaces, pore condensation occurs at pressures above the saturation pressure (i.e., at P/P0 > 1). In this case, we investigated the pore filling of water by the application of novel, liquid water intrusion/extrusion experiment, i.e. by applying the Washburn equation on the water intrusion branch (which reflects here the thermodynamic equilibrium vapor-liquid transition of a non-wetting fluid). Complementary molecular simulations provide density profiles of water on pristine and TMS-grafted silica surfaces, which agree with the obtained experimental data. Summarizing, we present a comprehensive and reliable methodology for assessing the hydrophilicity/hydrophobicity of siliceous nanoporous materials, which has the potential to optimize applications in heterogeneous catalysis and separation (e.g.chromatography).

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Current Status and Perspectives of the Thermomolecular Engine Developing

Cited by 9 publications

References 15 publications

Intrusion–Extrusion of Electrolyte Aqueous Solutions in Pure Silica Chabazite by in Situ High Pressure Synchrotron X-ray Powder Diffraction

Intrusion–Extrusion of Electrolyte Aqueous Solutions in Pure Silica Chabazite by in Situ High Pressure Synchrotron X-ray Powder Diffraction

Energetic Performance of Pure Silica Zeolites under High-Pressure Intrusion of LiCl Aqueous Solutions: An Overview

Quantitative Assessment of Hydrophilicity/Hydrophobicity in Mesoporous Silica by combining Adsorption, Liquid Intrusion and solid-state NMR spectroscopy

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