Solid ion exchange

Homogeneous liquid membrane electrodes. This type, which is in limited use, is sometimes considered as a solid ion-exchange electrode as the electroactive species, e.g., calcium dioctylphosphate, after being dissolved in an ethanol-diethyl ether solution of collodion, is left to "dry and can function as an ion-selective pellet in an electrode tip. Orion37 use these electrodes with PVC-gelled membranes for Ca2+, K+, BF4 and N03. ... 

Grubb, W. T. 1959. Batteries with solid ion exchange electrolytes. 1. Secondary cells employing metal electrodes. Journal of the Electrochemical Society 106 275-278. 

The equilibrium (also known as the Donnan effect) established across a semipermeable membrane or the equivalent of such a membrane (such as a solid ion-exchanger) across which one or more charged substances, often a protein, cannot diffuse. Diffusible anions and cations are distributed on the two sides of the membrane, such that the sum of concentrations (in dilute solutions) of diffusible and nondiffusible anions on either side of the membrane equals the sum of concentrations of diffusible and nondiffusible cations. Thus, the diffusible ions will be asymmetrically distributed across the membrane and a Donnan potential develops. 

The exchange of metal ions in solution with protons on a solid ion exchanger is an equilibirum process, as shown in Figure 11. 

Essentially the only source of flow in a solid ion-exchange membrane (ion-exchanger) is electro-osmosis. This is a flow induced by the interaction of the electric field with the space charge distributed in the fluid present in the solid. In this respect, electro-osmosis may be regarded as a relative of electro-convection in a hydrodynamically free solution. 

F. /on Exchange Chromatography. It is a process whereby a soln of ions is conducted thru a column consisting of an insoluble solid ion exchanger(such as ion exchange resin) saturated with a solvent. This action separates some of the constituents. This method was primarily designed for separation of fission products in connection with the work on atomic energy in the US(Refs 47a, 48a, 58, 78 86)... 

The limiting step in the kinetics of ion exchange in the zeolite is the interdiffusion of the electrolyte ions A zi and ions of the species B [24], In the case where the solid ion-exchanger particle is spherical (see Figure 7.9) and the particle diffusion control is the rate-determining process, then Fick s second law equation in spherical coordinates is [47]... 

Linear polyphosphates possess properties very similar to those of cross-linked, solid ion-exchange agents (Thilo, 1955). The behavior of polyphosphates as dissolved ion-exchange agents is yet further evidence of their ability to form complexes with counter-ions. Polyphosphates are known to be very good complexing agents for many metal ions (Van Wazer, 1958). This property is widely exploited in the fractionation of polyphosphates, and for other analytical purposes. 

MTBE is synthesized by a simple process in the liquid phase, over a solid ion exchange resin which catalyses the reaction of methanol with isobutylene. 

Cu-exchanged zeolite catalyst containing strong water tolerance and hydrothermal stability, although a method for preparation by using a solid ion exchange chemical transport technique has been suggested. 

Ion exchange techniques are used for the separation of relatively small amounts of high pure rare-earths. In this process, a rare-earth ion. in solution, exchanges with ions on a solid ion exchanger, a natural zeolite or a synthetic resin, which is normally called the resin [11]. 

Alkylation reactions, on solid ion exchange resins as heterogeneous Bronsted acids, obey Rideal kinetics (25), as shown in Equation 6 at low pressure (F olefin < 2 atm), where K 01 << 1, the rate law simplifies to Equation 7. 

Options 8 and 9. Other Effluent Treatments. Reverse osmosis is a physical process by which the majority of the effluent water is cleansed of polluting ions. However, a highly polluted reject-water stream also is produced. This reject stream is normally sent to evaporation ponds for further concentration and ultimate disposal of the pollutant solids. Ion exchange is a physiochemical process that similarly produces a pure-water stream and a lower volume stream of concentrated waste that must be evaporated. Both processes are more expensive than is Option 7, have the same general drawbacks, and have the additional problem of disposing their concentrated waste streams. 

Coion. Small ions, entering a solid ion exchanger, that have the same charge as that of the fixed ions. 

Liquid solid Ion exchange Electrode reactions (including plating) Enzyme reactions peptide synthesis Liquid phase olefin polymerization Cheese making High-fructose corn sweeteners... 

Grubb, W.T. Niedrach, L.W. Batteries with solid ion-exchange membrane electrolytes. II. Low-temperature hydrogen-oxygen fuel cells. J. Electrochem. Soc. 1960, 107, 131-135. 

The only deviation from this pattern is the DMFC (direct methanol fuel cell) which uses methanol as a fuel without intermediate reforming and microbial fuel cells that use sugar as a fuel and derive current from the metabolic activity of yeast. Both types use a solid ion exchange membrane type electrolyte (proton exchange membrane). 

PEMFCs have a solid ion exchange membrane made of sulfonated fluoropolymer, or a sulfonated polyetheretherketone (SPEEK) which is the electrolyte, and for the most part uses platinum catalysts. There are other materials in use for combination type membranes. It should be mentioned that currently SPEEK membranes do not hold up as well as the fluoropolymers such as Nafion , but research is ongoing to produce a more reliable and longer lasting membrane. 

The name ion chromatography applies to any modern method for chromatographic separation of ions. Normally, such separations are performed on a column packed with a solid ion-exchange material. But if we define chromatography broadly as a process in which separation occurs by differences in migration, capillary electrophoresis may also be included. 

Ion exchange Chemical reaction equilibrium Solid ion-exchanger... 

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