Chitosan-containing organoclays: Structural characterization and retention/removal of methylene blue

Abstract

Organoclays, composed of chitosan and stevensite-rich clay (RH) or kaolinitic-illitic clay (BN2), were structurally characterized, and their adsorption abilities for methylene blue (MB) were investigated by XRD, FT-IR, UV-vis spectroscopy and SEM. The effects of pH, ionic strength (I) and temperature (T) on MB desorption were evaluated by using the response surface methodology (RSM). The results showed that the chitosan was placed within interlamellar spaces of swelling clay minerals, and around clay and ancillary particles, and the kinetics of MB adsorption was generally controlled by film-diffusion. MB adsorption occurred spontaneously (–41 < ∆G° T > I.