Ion-exchange interaction

Many methods are available to the analyst ion interaction, ion exchange, ion exclusion, ion suppression, and ion pairing. 

The main conclusion from the above measurements is that a critical step in photodegradation is adsorption of the organic substrate on the surface. Therefore the parameters that control photodegradation are directly related to the parameters that govern adsorption processes, and include van der Waals forces, dipole-dipole interaction, ion-exchange, hydrogen bonding, hydrophobic interactions, n-n interactions, and donor-acceptor interactions. 

Silicas with an appropriate pore size are chemically modified to serve as reversed-phase, hydrophobic interaction, ion-exchange, and affinity packings for biopoly-... 

Activated diffusion of the adsorbate is of interest in many cases. As the size of the diffusing molecule approaches that of the zeohte channels, the interaction energy becomes increasingly important. If the aperture is small relative to the molecular size, then the repulsive interaction is dominant and the diffusing species needs a specific activation energy to pass through the aperture. Similar shape-selective effects are shown in both catalysis and ion exchange, two important appHcations of these materials (21). 

Silica Polymei Metal Ion Interactions in Solution. The reaction of metal ions with polymeric sihcate species in solution may be viewed as an ion-exchange process. Consequently, it might be expected that sihcate species acting as ligands would exhibit a range of reactivities toward cations in solution (59). Sihca gel forms complexes with multivalent metal ions in a manner that indicates a correlation between the ligand properties of the surface Si-OH groups and metal ion hydrolysis (60,61). For Cu +, Fe +, Cd +, and Pb +,... 

Graham-Uranoff They studied multicomponent diffusion of electrolytes in ion exchangers. They found that the Stefan-Maxwell interaction coefficients reduce to limiting ion tracer diffusivities of each ion. 

Table 16-1 classifies sorption operations by the type of interaction and the basis for the separation. In addition to the normal sorption operations of adsorption and ion exchange, some other similar separations are included. Applications are discussed in this section in Process Cycles. ... 

When more than one adsorbed species or more than two ion-exchanged species interact in some manner, equilibrium becomes more complicated. Usually, thermodynamics provides a sound basis for prediction. 

Despite the intrinsically nonspecific nature of ion-exchange and reversed-phase/hydrophobic interactions, it is often found that chromatographic techniques based on these interactions can exhibit remarkable resolution this is attributed to the dynamics of multisite interactions being different for proteins having differing surface distributions of hydrophobic and/or ionizable groups. 

The biogeochemical processes that generally describe the interaction of elements with particles are quite well known dissolution, flocculation, ion exchange, sorption, (co)precipitation, electron transfer, and biological uptake. In aquatic environments these reactions often occur simultaneously and competitively. In order to utilize marine tracers effectively, we must understand how elements are associated with particles and sediments. 

The two examples that have been given are simple and basic, and illustrate the principles of a TLC separation. Ion exchange material can also be bonded to the silica, allowing ionic interactions to be dominant in the stationary phase and, thus. 

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