Adsorption, nanoporous materials

In the past two decades, 129Xe NMR has been employed as a useful technique for the characterization of the internal void space of nanoporous materials. In particular, the xenon chemical shift has been demonstrated to be very sensitive to the local environment of the nuclei and to depend strongly on the pore size and also on the pressure [4—6], Assuming a macroscopic inhomogeneity resulting from a distribution of adsorption site concentrations, 129Xe NMR spectra of xenon in zeolites have been calculated, and properties such as line widths, shapes as well as their dependence on xenon pressure can be reproduced qualitatively. A fully quantitative analysis, however, remains difficult due to the different contributions to the xenon line shift. (See Chapter 5.3 for a more detailed description of Xe spectroscopy for the characterization of porous media.)... 

Benard, P., R. Chahine, RA. Chandonia, D. Cossement, G. Dorval-Douville, L. Lafia, P. Lachance, R. Paggiaro, E. Poirier, Comparison of hydrogen adsorption on nanoporous materials. J. Alloys Compd. 446-447, 380-384, 2007. 

Thommes, M. 2004. Physical adsorption characterization of ordered and amorphous mesoporous materials. In Nanoporous Materials Science and Engineering, edited by Lu, G. Q. Zhao, X. S. Imperial College Press, London, pp. 317-364. 

Thomas KM. Adsorption and desorption of hydrogen on metal-organic framework materials for storage applications comparison with other nanoporous materials, Dalton Trans 2009, 2009,1487-1505. 

Many applications of silica-based nanoporous materials such as adsorption, ion exchange, catalysis and sensing, require specific surface properties. Since the discovery of the MCM series of mesoporous materials [1], two main methods have been used to functionalize their large internal surface [2]. 

These findings enrich our knowledge of pillared clays and have potential applications in tailor-design nanoporous materials for adsorption and catalysis. 

Calculations of Pore Size Distributions in Nanoporous Materials from Adsorption and Desorption Isotherms... 

Two kernels of theoretical isotherms in cylindrical channels have been constructed corresponding to the adsorption and desorption branches. For a series of samples [2-4], we show that the pore size distributions calculated from the experimental desorption branches by means of the desorption kernel satisfactory coincide with those calculated from the experimental adsorption branches by means of the adsorption kernel This provides a convincing argument in favor of using the NLDFT model for pore size characterization of nanoporous materials provided that the adsorption and desorption data are processed consistently,... 

Adsorption of halocarbons in nanoporous materials current status and future challenges. 

Synthesis and Applications of Functionalized Nanoporous Materials for Specific Adsorption... 

Adsorption of Halocarbons in Nanoporous Materials Current Status and Future 721... 

R. Roque-Malherbe, Adsorption and Diffusion in Nanoporous Materials, CRC Press, Boca Raton, FL, 2007. 

The majority of adsorbents applied in industry has porous sizes in the nanometer region. In this pore-size territory, adsorption is an important method for the characterization of porous materials. To be precise, gas adsorption provides information concerning the microporous volume, the mes-opore area, the volume and size of the pores, and the energetics of adsorption. Also, gas adsorption is an important unitary operation for the industrial and sustainable energy and pollution abatement applications of nanoporous materials. 

On the other hand, in addition to adsorption properties, nanoporous materials are a group of advanced materials with other excellent properties and applications in many fields, for example, optics, electronics, ionic conduction, ionic exchange, gas separation, membranes, coatings, catalysts, catalyst supports, sensors, pollution abatement, detergency, and biology [1-42],... 

FIGURE 6.8 Representation of a standard volumetric adsorption apparatus. (Taken from Thommes, M., in Nanoporous Materials Science and Engineering, Lu, G.Q. and Zhao, X.S. (eds.), Imperial College Press, London, UK, 2004, 317. With permission.)... 

Gas, or vapor molecules, after the degasitication process, can go through the pore structure of crystalline and ordered nanoporous materials through a series of channels and/or cavities. Each layer of these channels and cavities is separated by a dense, gas-impermeable division, and within this adsorption space the molecules are subjected to force fields. The interaction with this adsorption field within the adsorption space is the base for the use of these materials in adsorption processes. Sorption operations used for separation processes imply molecular transfer from a gas or a liquid to the adsorbent pore network [2],... 

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