Exchange resins functional groups

Cation-exchange resins Functional groups Chemical formula... 

Anion-exchange resins Functional Groups Chemical Formula... 

Nitrogen and phosphor functionalized adsorbents for the adsorption of Co(II). Hereby, Amberlyst A2I was selected for its nitrogen functionality. It is a macroreticular polystyrene - crosslinked by divinylbenzene - anion exchange resin functionalized with an alkylamine group. As a phosphorous functionalized adsorbent, polymerbounded PPhj has been selected. It is a gel-type polystyrene - crosslinked by 2 [%] divinylbenzene - resin functionalized with a PPh2 group. 

The ion-exchange resin acts as a semipermeable membrane between the two aqueous phases, b and c. Ionized sample solutes are excluded from the interior water (b) and pass quickly through the column. Nonionic materials are not excluded and they partition between the two water phases, b and c. Thus, they pass more slowly through the column. Nonionic solutes differ in their degree of retardation by the resin phase because of (1) differing polar attraction between the solute and resin functional groups, (2) differing van-der-Waal forces between the solutes and the hydrocarbon portion of the resin. 

Our earlier attempts to identify both the formation and the stoichiometries of HAS(s) involv their retention on cation exchange resins and subsequent elution using dilute acid [1,9]. The technique relied on the assumptions that HAS,s) were small enough to enter the matrix of the resin (< 100 nm), that they were positively charged and that their retention by the resin functional groups would not alter the form in which they had entered the resin. We successfully applied this method in dilute mildly acidic solutions to identify HAS ) with Si Al ratios between ca. 0.2 and 0.7 and, at that time, we interpret these results as confirmation of the existence of one general form of HAS ) with an ideal Si Al ratio of 0.5. It was not until we had developed a method to... 

Ion-exchange resins are categorized by the nature of functional groups attached to a polymeric matrix, by the chemistry of the particular polymer in the matrix, and by the porosity of the polymeric matrix. There are four primary types of functionaHty strong acid, weak acid, strong base, and weak base. Another type consists of less common stmctures in specialty resins such as those which have chelating characteristics. 

Strong"Base. Strong base anion-exchange resins have quaternary ammonium groups, - NR OH , where R is usually CH, as the functional exchange sites (see Quaternary ammonium compounds). These resins are used most frequentiy in the hydroxide form for acidity reduction. 

Weak Base. Weak base anion-exchange resins may have primary, secondary, or tertiary amines as the functional group. The tertiary amine -N(CH2)2 is most common. Weak base resins are frequentiy preferred over strong base resins for removal of strong acids in order to take advantage of the greater ease in regeneration. 

The resins used are highly cross-linked organic polymers with acidic functional groups. The most common of the resins used are sulfonated copolymers of styrene and divinylben2ene (see Ion exchange). 

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