Novel hydrogel composite for the removal of water-soluble cationic dye

A novel hydrogel composite was prepared by incorporating Laponite RDS clay into poly(acrylic acid-co-N-vinyl-2-pyrrolodone) hydrogel during in-situ polymerization, and investigated with respect to its adsorption kinetics and isotherm toward Crystal Violet, a widely used cationic dye. It was found that the adsorption kinetics of Crystal Violet onto the hydrogel composite was consistent with the pseudo-second-order model. Compared with pure hydrogel, the hydrogel composite is characterized by greater amounts being adsorbed at equilibrium, and a higher rate constant and initial adsorption rate. By analyzing the experimental data using the Langmuir isotherm equation, an enhanced adsorption capacity was found for the hydrogel composite. Such material is expected to be a good adsorbent for water pollutants such as cationic dyes and treatment of these organic contaminants from wastewater. (c) 2006 Society of Chemical Industry.