Metal ion binding properties of poly(N-vinylimidazole) hydrogels

Abstract

ABSTRACT:The ability of poly(N-vinylimidazole) hydrogels to bind Cu(II), Co(II), Ni(II), Zn(II), Cd(II), Pb(II), Hg(II), Na(I) and Ca(II) cations, as well as uranyl, vanadium, rhenium, and molybdenum complexes, was studied by a batch equilibrium procedure using atomic absorption spectroscopy and UV-Vis spectrophotometry. The optimum pH for ion adsorption was determined in any case. The influence of the crosslinking degree of the hydrogel on the sorption kinetics and the sorption capacity at equilibrium were also studied. Sorption from the binary mixture Cu(II) / U(VI) was also analyzed at the optimum pH. Elution of the ions adsorbed from single and binary solutions was achieved in all cases. A selective desorption of loaded hydrogels with two types of ions was attained. The general conclusion is that poly( N-vinylimidazole) hydrogels are excellent materials for retention of all the ions studied here [except for Pb(II), Na(I), and Ca(II)]. The elution, which can be selective, allows regeneration of the hydrogel.

pH-dependence of the swelling capacity of poly(N-vinylimidazole) hydrogels

“…Poly(N-vinylimidazole) hydrogels were synthesized [19][20][21][22][23] by radical crosslinking polymerization of N-vinylimidazole (VI) and N,N 0 -methylenebisacrylamide (BA) in aqueous solution, with AIBN (6 Â 10 À3 M) as initiator. N-vinylimidazole, purchased from Aldrich, was distilled under reduced pressure at 55 8C just prior use.…”

“…Besides, they have several remarkable properties. They regulate the pH of the bath in which they are immersed, [20,21] in ethanol they swell or collapse depending on the microstructure controlled by the composition of the feed [19] and they take up heavy metal ions [22,23] from aqueous solutions. Poly[(N-vinylimidazole)-co-(sodium styrenesulfonate)] hydrogels [24,25] have also several peculiar properties, for example, for some gel compositions dry discs swell up readily and then, spontaneously, they deswell and collapse.…”

Removal of Hg(II) from acid aqueous solutions by poly(N-vinylimidazole) hydrogel

“…1 The average molecular weight between crosslinks of the sample employed in this work was 3.2 10 4 , and its swelling ability in pure water was 4.32 g of water per gram of dry gel.…”

“…1 The aim of this article is to study the ability of poly(vinylimidazole) hydrogel to bind mercury ions under different conditions as well as the recovery of the hydrogel by nitric acid.…”

New copolymers with triazole pendant groups: Synthesis, characterization and their application to remove heavy metals

“…Pollution in water concern to worldwide due the toxic effect on humans hence it needs the immediate attention of researchers and environmentalists [12,13]. Polymer resins and hydrogels bearing electron donor groups have the ability to bind metal cations [15][16][17][18][19][20]. Mercury is generally considered to be one of the most toxic metals found in the environment [21] and that is why the discharge limit of waste water streams has been fixed by law in very small values.…”