Adsorptive behavior of rice bran-based composites for malachite green dye: Isotherm, kinetic and thermodynamic studies

Rice bran (RB) composites were prepared with polyaniline, starch, polypyrrole, chitosan aniline and chitosan pyrrole and employed for the adsorption of Malachite green (MG) dye. Composites doses, pH, contact time, MG dye initial concentration and temperature effects on dye adsorption were studied. Native RB, polyaniline, starch, chitosan pyrrole, polypyrrole and chitosan aniline composites showed-the maximum MG dye adsorptions of 143.17, 147.47, 140.85, 122.5, 145.03 and 55 (mg/L) for 200 mg/L dye initial concentration, 50 degrees C temperature, 50-60 min contact time, 0.05 g/L adsorbent doses in the pH range of 5-7, respectively. Pseudo-second-order kinetic model and Freundlich isotherm fitted well to the adsorption data and intraparticle diffusion was the dye adsorption rate limiting step. Thermodynamic study revealed the endothermic and energetically stable adsorption nature MG dye onto RB composites. Results showed that composites have potential for MG adsorption and are potential candidates for the adsorption of dyes from textile wastewater. (C) 2017 Elsevier B.V. All rights reserved.