Implementation of response surface methodology in physi-chemisorption of Indigo carmine dye using modified chitosan composite

Abstract

A composite of chitosan with Mohr's salt was prepared by microwave irradiation method. This novel chitosan-ferrous ammonium sulphate composite was characterized using various techniques like FT-IR, SEM, EDX, TGA-DTA, XRD and pHpzc. The material was used for adsorptive removal of Indigo Carmine dye from aqueous solution using batch experiments as well as Response Surface Methodology. The screening experiments in accordance with Plackett-Burman design followed by Central Composite Design led to optimization of various operating parameters. When the batch adsorption experiments were carried out under the conditions predicted by Central Composite Design modelling, more than 98% dye adsorption was observed. The adsorption capacity was found to be 76.64 mg g−1 in accordance with Langmuir adsorption isotherm and pseudo-second-order kinetics model. The process was found to be feasible, endothermic and entropy driven as indicated by the thermodynamics studies.