Adsorption and diffusion

Synge, RLM, Experiments on Electrical Migration of Peptides and Proteins Inside Porous Membranes Influences of Adsorption, Diffusion, and Pore Dimensions, Biochemical Journal 65, 266,1957. 

Molecular attraction (surface tension, adsorptive, diffusive, and osmotic forces)... 

Understanding the adsorption, diffusivities and transport limitations of hydrocarbons inside zeolites is important for tailoring zeolites for desired applications. Knowledge about diffusion coefficients of hydrocarbons inside the micropores of zeolites is important in discriminating whether the transport process is micropore or macropore controlled. For example, if the diffusion rate is slow inside zeolite micropores, one can modify the post-synthesis treatment of zeolites such as calcination, steaming or acid leaching to create mesopores to enhance intracrystalline diffusion rates [223]. The connectivity of micro- and mesopores then becomes an... 

Two years ago, Advances in Catalysis featured a chapter on chemisorbed intermediates in electrocatalysis. In this issue we follow up with a chapter by Wendt, Rausch, and Borucinski, Advances in Applied Electrocatalysis. The successful commercial application of electrocatalysis requires a detailed, fundamental knowledge of the many catalytic phenomena such as adsorption, diffusion, and superimposition of catalyst micro- and nanostructure on the special requirements of electrode behavior. Considerable understanding of the status and limitations of electrolysis, fuel cells, and electro-organic syntheses has been obtained and provides a sound basis for future developments. 

Silicon Solid-state Chemistry.—Contrary to the pattern adopted in previous volumes, the chemistry of aluminosilicates and zeolites will not be discussed here the data published during the period of this Report associated with these materials are considered in detail in Chapter 3. In this section, silicon dioxide and the silicates will be described separately emphasis will be laid on the inorganic chemistry of these compounds, and papers describing solely their catalytic, adsorption, diffusion, and other similar properties will not be considered. 

A.B. Shelekin, A.G. Dixon and Y.H. Ma, Adsorption, diffusion and permeation of gases in microporous membranes III. Application of percolation theory to interpretation of porosity, tortuosity and surface area in microporous glass membranes, /. Membr. Sci., 83 (1993) 181. 

We now report how theoretical methods can be used to provide information on the adsorption, diffusion, and reactivity of hydrocarbons within acidic zeolite catalysts. In Section A, dealing with adsorption, the physical chemistry of molecules adsorbed in zeolites is reviewed. Furthermore, in this section the results of hydrocarbon diffusion as these data are obtained from the use of the same theoretical methods are described. In Section B we summarize the capability of the quantum-chemical approaches. In this section, the contribution of the theoretical approaches to the understanding of physical chemistry of zeolite catalysis is reported. Finally, in Section C, using this information, we study the kinetics of a reaction catalyzed by acidic zeolite. This last section also illustrates the gaps that persist in the theoretical approaches to allow the investigation of a full catalytic cycle. 

The carbon-deposition process of EUV optics has been described to involve adsorption, diffusion, and dissociation of hydrocarbons at the surface of the... 

Studies of adsorption, diffusion and molecular simulation of cyclic hydrocarbons in MFI zeolites... 

Naturally, a fundamental requirement is the determination of the structure of the molecular sieves imder study (cf. Voliune 2) through techniques such as X-ray diffraction, neutron scattering, electron microscopy and so on. However, a remarkably broad variety of methods and tools are at our disposal for characterizing the physical and chemical properties of molecular sieves. Voliune 4 of the series Molecular Sieves - Science and Technology focuses on the most widely used spectroscopic techniques. Thereby, the contributions to this voliune not only review important applications of these techniques, but also comprise, to a greater or lesser extent, the basic principles of the methods, aspects of instrumentation, experimental handling, spectra evaluation and simulation, and, finally, employing spectroscopies in situ for the elucidation of processes with molecular sieves, e.g. synthesis, modification, adsorption, diffusion, and catalysis. 

AUotropes.— The chemistry of the allotropic forms of carbon which has been abstracted for this Report concentrates on their structural, spectroscopic, and intrinsic chemical properties those papers which describe solely their catalytic, adsorption, diffusion, and other similar properties have been excluded. 

When low molecular substance or solvent molecules migrate through solid plastics this process is called permeation. Basically, substance transport in permeation takes place in three steps adsorption, diffusion, and desorption of the migrating molecule [3, 21, 22]. Figure 30 provides a schematic presentation of the transport mechanism involved in permeation. 

In 1983, a NATO Advanced Study Institute was organized in Alcabideche (Portugal) to establish the State-of-the-Art in Zeolite Science and Technology and to contribute to a bett understanding of the structural properties of zeolites, the configurational constraints they may exert, and their effects in adsorption, diffusion, and catalysis. 

Ban S, Huang C, Yuan XZ, Wang H. Molecular simulation of gas adsorption, diffusion, and permeation in hydrated Nafion membranes. J Phys Chem B 2011 115(39) 11352-8. 

In order to understand the dynamics of gas-surface interaction, it is necessary to determine how much energy is exchanged between the gas and surface atoms through the various energy-transfer channels. In addition the kinetic parameters (rate constants, activation energies, and preexponential factors) for each elementary surface step of adsorption, diffusion, and desorption are required in order to obtain a complete description of the gas-surface energy transfer process. 

Theories of adhesion K W ALLEN General introduction to mechanical, adsorption, diffusion and electrostatic theories... 

Adsorption, diffusion, and reaction in ZSM-5 and siUcaUte have been studied extensively. For adsorption, it has been used as a selective sorbent for VOC... 

For the intended noncovalent interactions between the molecular building blocks to develop in order to form the desired two-dimensional (2D) supramolecular patterns, several parameters, which are essentially molecular adsorption, diffusion, and the underlying interaction energetics, have to be balanced. Surface diffusion comprising lateral and rotational mobility is required, such that the individual... 

In fixed-bed adsorption, diffusion and mixing of metal ions in fluids occur due to adsorbate concentration gradients and non-uniformity of fluid flow. This gives rise to axial dispersion in the main direction of fluid flow and radial dispersion in the direction transverse to the main flow. The former is usually undesirable since it reduces separation efficiency, whereas the latter is desirable as it equalizes concentrations at the same axial position and reduces axial dispersion. For the simple case of singlephase flow in a packed bed of cylindrical configuration, the conservation equation for a metal ion in the solution is... 

Adsorption, Diffusion, and Exchange Processes in Proton Exchange Membrane Fuel Cell Catalysts (Catalytic Processes in Proton Exchange Membrane Fuel Cells)... 

ADSORPTION, DIFFUSION, AND EXCHANGE PROCESS IN PROTON EXCHANGE... 

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