Synthesis of Hybrid Ion Exchanger for Rhodamine B Dye Removal: Equilibrium, Kinetic and Thermodynamic Studies

A systematic method was employed to synthesize organic–inorganic-based hybrid ion-exchanger for the removal of rhodamine B dye from aqueous solution. Ion exchange capacity of the hybrid ion exchanger was found to be 2.4 mequiv/g. The morphology, chemical structure, and elemental analysis of the synthesized hybrid ion exchanger were investigated by SEM, FTIR, and EDS analytical techniques. Effects of different reaction parameters such as contact time, temperature, and pH were also investigated. The adsorption kinetics of rhodamine B molecules onto synthesized hybrid ion exchanger were studied and compared using psudo-first-order and pseudo-second-order, and it was found that pseudo-second-order best reprented the adsorption process. The Weber–Morris intraparticle diffusion result showed that intraparticle diffusion is not the rate limiting step. The adsorption isotherm model Langmuir, Freundlich, Dubinin–Radushkevich, Tempkin, and Redlich–Peterson isotherms were studied, and it was found that the Langmuir is the best-fitting models for the experimental results. An increase in temperature resulted in a decrease in rhodamine B dye removal, suggesting that the adsorption process was exothermic. Maximum dye removal was found to be 98.3%. The kinetics of adsorption followed a pseudo-second-order rate equation.