Investigation of an adsorbent based on novel starch/chitosan nanocomposite in extraction of indigo carmine dye from aqueous solutions

Abstract

Treatment of corn starch using pullulanase to prepare high yield of starch nanoparticles (StNPs) in a short time is one of the best ways of green industry of StNPs in comparison with other preparation procedures. Morphology of surface, particle size, function groups behavior and crystalline structure were investigated by using Scanning electron microscope (SEM), Dynamic light scattering (DLS), Transmission electron microscope (TEM), Fourier transforms infrared spectroscopy and X-ray diffraction. Starch nanoparticles can be used with chitosan to generate a novel composite to remove dyes from aqueous solutions. Indigo carmine dye was remediated with chitosan starch nanoparticle composite to evaluate the adsorption efficiency of such composite. Batch experiments were done to check the optimum pH, contact time, adsorbent dose, initial dye concentration and temperature to assess the kinetic data from isotherm of adsorption. The obtained results are fitted with pseudo second order and Langmuir isotherms. Free Gibbs energy (∆G°), enthalpy (∆H°) and entropy (∆S°) of the sorption parameters indicated spontaneous and endothermic adsorption process.