Novel PAAm/Laponite clay nanocomposite hydrogels with improved cationic dye adsorption behavior

A nanocomposite (NC) hydrogel was prepared by incorporating the nanoclay (Laponite (Lap) XLS) into a poly(acrylamide) (PAAm) hydrogel by the in situ polymerization method without any organic cross-linker. The parameters pertaining to the swelling (Q) and diffusion (D) of water for the PAAm/Lap NC hydrogels were estimated. The crystal violet (CV) dye adsorption properties of the PAAm/Lap NC hydrogels were investigated. The adsorption of CV dye by the hydrogel increases as the concentration of the dye increases. The cationic dye adsorption ability of the NC hydrogel increased with increasing clay content in the NC hydrogel. The NC hydrogels containing CV dye were characterized by FT-IR. A sigmoidal type of adsorption isotherm was observed for the CV-NC hydrogels. The effects of heat treatment on the dye adsorption behavior of the NC hydrogels were studied. (c) 2007 Elsevier Ltd. All rights reserved.