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.
It was successful synthesized the ion exchange resin poly([(2-methacryloyloxy) ethyl]) trimethylammonium chloride) PClMETA by radical polymerization to study the removal properties towards vanadium (V) and molybdenum (VI) and compared with the commercial resin AmberliteIRA-402 which contains the same functional group. The resin was characterized by FT-IR and SEM. Parameters including water adsorption capacity, effect of the pH, maximum retention capacity of the metal ions, elution, regeneration, adsorption time, and adsorption isotherms were studied. All the studies were carried out in Batch and Column equilibrium procedures. Thermodynamic parameters such as enthalpy, entropy, and free energy were calculated. The PClMETA resin showed higher capacity to remove V(V) and Mo(VI) from water solution than Amberlite IRA-402 commercial resin. The higher capacity displayed by PClMETA resin was attributed to the higher degree of swelling and different structure that Amberlite IRA-402 resin.
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