Polyacrolein-isonicotinic acid hydrazone and polyacrylic acid-thiohydrazide resins-synthesis and sorption properties for precious and base metals

Abstract

Abstract. This investigation carries on previous studies on polyacrolein-styrene resins. Further attempts were made to convert the reactive aldehyde groups of the polymeric support to functional acrolein-isonicotinic acid hydrazone (P-NHZ) or acrylic acid-thiohydrazide derivatives (P-THZD). The conditions of synthesis and the basic sorption and desorption properties of the polymers synthesized are described. For gold and platinum group metals the resins show differences in loading capacities, rates of simultaneous sorption in static conditions and efficiencies in column tests. The elufion by thiourea solution was utilized to separate Au, Pd and Pt from an excess of base metals. The P-NHZ resin seems to be more advantageous than the sulfur containing P-THZD resin.Key words: Polyacrolein-isonicotinic acid hydrazone resin, polyacrylic acid-thiohydrazide resin, polyacrolein-styrene resin, precious metals.In analytical chemistry and in hydrometallurgical processes the effective removal of traces of platinum group metals and gold from aqueous solutions by means of adsorbing agents requires stability and high selectivity of these materials in strongly acidic media [1][2][3]. The attachment of metal complex forming ligands to an insoluble resin matrix is a common preparative route to obtain selectively chelating resins [4]. The sorption properties of this type of ionexchange resin is determined by the metal complex * To whom correspondence should be addressed forming properties of the functional groups and also by the morphology of the polymeric matrix [2,5].Corresponding to Pearson's HSAB-concept promising selective sorption properties towards noble metal ions were expected from polymer bonded functional groups which contain donor N-and S-atoms, such as isothiouronium-[6-8], dithiocarbamate-[9], formazan-and tetrazolium groups [10][11][12][13].The common macroporous resin matrix is based on copolymers of polystyrene, however, in addition polyacrylonitriles, polymethacrylates and cellulose have also been chemically modified. In our previous studies the macroporous crosslinked polyacroleinstyrene resin matrix could be successfully functionalized [14][15][16][17], due to the reactivity of the acrylic aldehyde group. It reacts easily with amino groups so that a serial of chelating resins have been obtained. For example, functional aldehyde-hydrazone (P-HZ) and phenylhydrazone resins (P-PHZ) [17] were synthesized. The present contribution describes the synthesis and sorption properties of polyacroleinisonicotinic acid hydrazone and polyacrylic acidthiohydrazide resins.

Preparation and characterization of photocured thiol‐ene hydrogel: Adsorption of Au(III) ions from aqueous solutions

“…Moreover, S is poor in protonation and it is effective in coordinating with soft metal ions 24. Some attempts have been made to synthesize polymers containing donor sulfur atoms, such as thiol,23, 24 thiosemicarbazide,25 2‐mercaptobenzothiazole,26 and thiohydrate 27. But thiol‐ene‐based hydrogels have not been reported in the metal adsorption literature.…”

Synthesis and characteristics of chelating fibers containing imidazoline group or thioamide group

“…Ion exchange (or chelating) resins are being developed continuously. Polyacrolein‐isonicotinic acid hydrazone and poly(acrylic acid)‐thiohydrazide resins6 and imdazoline‐based7, 8 and formazan‐ and tetrazolium‐containing9–11 ion exchangers show promising adsorption capacity for noble metals. However, the use of these gel–structure granular exchangers and porous copolymers in the separation and preconcentration of trace noble metals is limited because of their slow sorption rate.…”