The preparation and characterization of poly(acrylic acid-co-methacrylamide) gel and its use in the non-competitive heavy metal removal

Abstract

Poly(acrylic acid-co-methacrylamide), P(AA-co-MAAm), and poly(acrylic acid), PAA, gels were prepared and the use of these gels in the non-competitive removal of Pb(2+), Cu(2+), and Cd(2+) ions from aqueous solutions was investigated at room temperature. Characterization of the polymers was performed by FTIR spectroscopy both before and after adsorption of metal ions on P(AA-co-MAAM) or PAA. The equilibrium swelling values (ESVs) of both polymers were determined by gravimetric method. During the adsorption of metal ions on both polymers, residual metal ion concentration in the solution (by atomic absorption spectrophoto meter (AAS)) and the solution pH were measured. The kinetics of the adsorption process was determined from the experimental results. Pseudo-first and second-order plots and the correlation coefficients showed that the kinetics of non-competitive adsorption of Pb(2+), Cu(2+), and Cd(2+) ions on P(AA-co-MAAM) or PAA is correlated best with pseudo-second-order process. While the removal order in the non-competitive adsorption of heavy metal ions on PAA was Pb(2+) (2.60 mmol g(-1)) > Cu(2+) (1.04 mmol g(-1)) > Cd(2+) (0.88 mmol g(-1)), it was in the order of Pb(2+) (1.85 mmol g(-1)) > Cd(2+) (0.70 mmol g(-1)) > Cu(2+) (0.64 mmol g(-1)) for P(AA-co-MAAM) copolymer. The introduction of MAAm into PAA decreased the metal ion removal capacity of copolymer for Pb(2+) and Cu(2+) ions considerably, but it did not significantly affect that for Cd(2+) ion. Copyright (C) 2008 John Wiley & Sons, Ltd.