Improved Stability of Starch@Layered-Materials Composite Films for Methylene Blue Dye Adsorption in Aqueous Solution

Abstract

In this present study, composites films of starch (St), Starch/CTA-bentonite (S@CB) and Starch/CTA-magadiite (S@CM) were fabricated by a solution casting process using glycerol as a plasticizer. The prepared samples were tested for the adsorption of cationic MB dye. The composites were characterized by X-ray diffraction XRD, Fourier transform infrared spectroscopy FTIR and scanning electronic microscopy SEM. These characterizations confirmed the interaction and immobilization of the modified solids as well as their commendable dispersed in the starch matrix. Equilibrium adsorption data of MB was carried out at 298 K. Two isotherm models (Freundlich and Langmuir) were tested for modeling the adsorption isotherms by the nonlinear form. Higher adsorption capacity and improved stability were achieved by composite films. The obtained data showed that the adsorption of MB dye on both composite films followed the Langmuir adsorption isotherm model and their kinetics was followed by the pseudo-second order model. The maximum adsorption values of MB dye were 89.82 and 76.59 mg/g for S@CB and S@CM composites, respectively.