Adsorption of Acid Red dye from aqueous solution using quaternized chitosan microspheres

Abstract

In this study, quaternized chitosan microspheres (QCMS) were prepared and their adsorption performance of Acid Red 18 from aqueous solution was studied. Equilibrium was attained within 120 minutes and maximum removal of 94.06% was achieved. Langmuir and Freundlich isotherm models have been investigated. The maximum capacity obtained from the Langmuir model is 142.15 mg.g(-1). Pseudo-first order and pseudo-second order kinetic models have been used for experimental data. The kinetic process was described by a pseudo-second-order rate equation very well. The calculated thermodynamic parameters (Delta H degrees = -12.67 kJ.mol(-1); Delta G degrees = -4.67 to -5.61 kJ.mol(-1) and Delta S degrees = -24.78 K-1.mol(-1)) showed that the adsorption of Acid Red 18 is feasible, spontaneous and endothermic in nature. The results of the present study indicated that the QCMS could be considered as a potential adsorbent for Acid Red 18 in aqueous solutions.