Enhanced swelling and adsorption properties of AAm-AMPSNa/clay hydrogel nanocomposites for heavy metal ion removal

Novel type hydrogel-clay nanocomposites based on the acrylamide (AAm)-2-acrylamido-2-methylpropane sulfonic acid (AMPS) sodium salt and clay were synthesized via in situ copolymerization in aqueous solution. Samples were characterized by determining total basic group (TGB) content and swelling degree, XRD analysis, and FTIR spectroscopy. Effects of monomer ratio and clay amount on the swelling properties of the samples were investigated. It was found that the hydrogel/clay nanocomposites exhibited improved swelling capacity compared with the hydrogels. Samples were used to remove heavy metal ions (Cu (II), Cd (II), and Pb (II)) from aqueous solution in competitive and non-competitive conditions for the first time. The effects of time and pH of the initial metal ion solution on the adsorption capacity were investigated and selectivity properties of the samples were evaluated. It was found that incorporation of a low amount of clay (10% (wt)) into the polymer structure increased the heavy metal ion adsorption capacity of the sample. It was concluded that the AAm-AMPS/clay nanocomposites could be used as novel type, fast-responsive, and high capacity sorbent materials in heavy metal removing processes. Copyright (c) 2007 John Wiley & Sons, Ltd.