Isotherm and Thermodynamics Study of Congo Red and Procion Red Adsorption over Natural and Zn/Fe Pillared Bentonite

Abstract

The effect of initial Congo Red and Procion Red concentration on isotherm adsorption and thermodynamic adsorption study using natural and Zn/Fe Pillared bentonite have been conducted. The adsorbents were also characterized by Fourier transform infrared (FTIR), X-Ray Diffraction (XRD), and Scanning electron microscope-energy dispersive X-Ray analysis (SEM-EDX). The study showed that the optimum dye removal of Congo Red and Procion Red was obtained at the initial dye concentration of 80 mg/L. The adsorption isotherm study showed that the Congo Red and Procion Red adsorption on natural and Zn/Fe Pillared bentonite followed the Freundlich isotherm model. The adsorption thermodynamics study showed that the adsorption of Congo Red and Procion Red occurred endothermically, wheraas the positive value of entropy indicated a high level of disorder of adsorption for both dyes. Furthermore, the FTIR, XRD, and SEM-EDX analysis showed that the pillarization of Zn/Fe on bentonite successfully well occurred, and it could be concluded that the adsorption of Congo Red using natural and Zn/Fe pillared bentonite showed a better adsorption process than Procion Red.