Sorption applications

Layered solids such as graphite are interesting in separation and sorption applications and can be doped to give interesting materials properties as in Li ion batteries. Their intercalation behaviour is best described by the Daumas-Herold model. 

The calculation of the volume of molecules is fundamental not only for the study of packing, but also in the computer simulation of the dynamics and fundamental physical properties of macromolecules such as proteins and nucleic acids [23], Likewise, the determination of the void space within any microporous material is of interest in sorption applications [28],... 

Comprehensive review papers on the sorption properties of natural zeolites can be found in literature [72,73]. Referring in particular to the main sedimentary zeolites, the last two columns in Table 2 show some structural features of interest for sorption applications. Chabazite, clinoptilolite, faujasite and mordenite, which couple reasonably large to large window sizes with wide inner volumes (except mordenite), appear the most suitable materials for adsorption processes. 

Some frameworks consist only of cages with a maximum ring size of six and have no channels (e.g. the purc-silica clathrasils), but the majority have at least 8-ring channels. These channels can intersect to form 2- and 3-dimensional channel systems, and this can be a critical feature for catalytic or sorption applications. For example, a 1-dimensional channel is much more easily blocked by the formation of coke deposits than is a higher dimensional one where detours are possible. 

The sorption applications include regeneration of porous beds, preparative scale supercritical chromatography, simulated moving beds, thermal swing schemes, and adsorp-tion/desorptions cycles. Although initial applications of supercritical fluids in this domain were on regeneration of porous beds, more recent emphasis on fractionation best reflects... 

One of the most conamon uses of the BET isotherm is for determining the surface area of finely divided solids by physical adsorption. Such information can be of great importance in a number of areas including heterogeneous catalysis and various sorption applications. While the BET model for multilayer adsorption contains several potential sources of error due to the assumptions of the absence of lateral interactions between adsorbed molecules, the... 

For carbon dioxide sorption applications, apart from the amine grafting of POFs, other functional groups with different polarities also contribute to the improvement of the carbon dioxide sorption capacity. Combined with the simulations, the isosteric heats of adsorption (Qst) of modified POFs are in the order of -COOH >-(0H)2 NH2 (0113)2 non-functionalized framework. Selecting the optimal reaction route to graft these specific units on POFs is one of the hot directions of the PSM of POFs. 

Although a few of these metal-organic supercontainers have a comparatively higher surface area that many of the molecular assemblies discussed above, they tend to undergo partial or complete collapse of the solid state packing upon solvent removal, limiting the use of these materials for gas sorption applications. 

There are three different categories of application for functionalized membranes separation, sorption and catalytic applications. For separation, the modified membranes must allow the selective permeation of the desired chemical species and can be prepared, for example, by layer-by-layer (LbL) assembling. In sorption applications, the modified membranes act as adsorbents, which can also lead to separation and capture. However, these membranes need to be regenerated before they can be reused. Finally, functionalized membranes for catalytic applications may include enzymes or immobilized nanoparticles that act as catalysts and convert the reactants into products as they pass through the membrane pore. Porous membrane supported catalytic applications not only provide a way for catalyst immobilization, avoiding the need for its subsequent removal from the reaction mixture, but also lead to improved mass-transport conditions, since this transport is mainly done through the pores. 

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