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Ion-exchange resin beads. An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange, that is also known as an ionex. [1] It is an insoluble matrix (or support structure) normally in the form of small (0.25–1.43 mm radius) microbeads, usually white or yellowish, fabricated from an organic polymer substrate.
Ion-exchange resin beads Ion-exchange column used for protein purification. Ion exchange is a reversible interchange of one species of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid. Ion exchange is used in softening or demineralizing of water, purification of chemicals, and separation ...
The resin has a higher affinity for highly charged countercations, for example by Ca 2+ (calcium) in the case of water softening. Correspondingly, anion-exchange resins are typically provided in the form of chloride Cl −, which is a highly mobile counteranion. Counterions are used in phase-transfer catalysis.
The resin is a weak exchanger because it is only partially ionized over most pH values, and an efficient separation with DEAE-C chromatography requires a specific, narrow pH range. [ 8 ] Cellulose, dextran, agarose, and other insoluble complexes are unaffected because they compose inert matrices, hence why they are so often derivatized with ...
Dowex chelating resin A-1, also known as Chelex 100, is based on iminodiacetic acid in a styrene-divinylbenzene matrix. Dowex A-1 is available commercially and is widely used to determine general properties of chelating resins such as rate determining step and pH dependence, etc. Dowex A-1 is produced from chloromethylated styrene ...
For example, they are employed as counterions for the 14 valence electron cations [(C 5 H 5) 2 ZrR] + (R = methyl or a growing polyethylene chain). Complexes derived from non-coordinating anions have been used to catalyze hydrogenation , hydrosilylation , oligomerization , and the living polymerization of alkenes .
An ion-exchange membrane is generally made of organic or inorganic polymer with charged (ionic) side groups, such as ion-exchange resins. Anion-exchange membranes contain fixed cationic groups with predominantly mobile anions; because anions are the majority species, most of the conductivity is due to anion transport.
Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. [1] Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. [ 2 ]