Water-soluble copolymers of 1-vinyl-2-pyrrolidone and acrylamide derivatives: Synthesis, characterization, and metal binding capability studied by liquid-phase polymer-based retention technique

Radical copolymerizations of 1-vinyl-2-pyrrolidone with acrylamide and N,N' -dimethylacrylamide at different feed ratios were investigated. The copolym ers were characterized by Fourier transform infrared spectroscopy, H-1 NMR, and C-13 NMR spectroscopy. The copolymer composition was determined from t he H-1 NMR spectra and found to be statistical. The metal complexation of p oly(acrylamide-co-1-vinyl-2-pyrrolidone) and poly(N,N'-dimethylacrylamide-c o-1-vinyl-2-pyrrolidone) for the metal ions Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Pb(II), Fe(III), and Cr(III) were investigated in an aqueous phase . The liquid-phase polymer-based retention method is based on the retention of inorganic ions by soluble polymers in a membrane filtration cell and su bsequent separation of low-molecular compounds from the polymer complex for med. The metal ion interaction with the hydrophilic polymers was determined as a function of the pH and the filtration factor. Poly(N,N-dimethylacryla mide-co-2-vinyl-2-pyrrolidone) showed a higher affinity for the metal ions than poly(acrylamide-co-1-vinyl-2-pyrrolidone). According to the interactio n pattern obtained, Cr(III) and Cu(II) formed the most stable complexes at pH 7. Pb(II) and Zn(II) were not retained. (C) 1999 John Wiley & Sons, Inc.