The use of palmitoyl hydroxyquinoline-functionalized amberlite XAD-2 copolymer resin for the preconcentration and speciation analysis of gallium(III)

Gallium (Ga) is a valuable element in the electronics industry for manufact uring semiconductors and lasers. The processing of bauxite ores for the rec overy of Ga, as well as high-level purification of the raw Ga product as re quired by electronic applications, necessitate effective speciation analysi s of this element. For differentiating chemically important Ga(III) species , the Amberlite XAD-2 polystyrene-divinylbenzene copolymer was chloromethyl ated using AlCl3 as a catalyst, and later, 5-palmitoyl-8-hydroxyquinoline w as covalently bound to this chloromethylated product via Friedel-Crafts rea ction, resulting in the synthesis of a Ga-specific resin (Amberlite XAD-2-P .Ox). This resin has been shown to preconcentrate Ga selectively from basic alumi nate solutions. The investigation of the effect of acidity on Ga recovery r evealed that Ga was quantitatively retained on the resin between pH 3 and 7 . The sorbed Ga could be eluted with 1 M HCl. A 100-mL volume of 2 ppm Ga s howed 100% uptake by 10 g of resin using a now rate of 1 mL/min. Here, all simple inorganic salts of Ga (e.g., Ga(III) nitrate, chloride, perchlorate) , as well as the aquated Ga3+ (hexaaqua-complex) species, exhibit quantitat ive retention. On the other hand, oxalate-, tartrate-, citrate-, acetylacetonate, and EDTA complexes of gallium(III) were not retained by the resin under identical c onditions. Thus, the synthesized chelating cation-exchanger showed selectiv e affinity to simple inorganic Ga(III) salts, in a way acting as an ion-sel ective electrode for Ga3+ while excluding coordinatively saturated stable G a-complexes. The developed ion-exchange procedure was used to separate gall ium from arsenate in a commercial gallium arsenide sample, followed by Ga d etermination without interference.