Kinetics, isotherms and thermodynamics study of eosin yellow dye adsorption from aqueous solutions by MnO2@rGO nanocomposite

This study explores the use of MnO2@rGO nanocomposite as an adsorbent for Eosin Y dye. It was found that equilibrium for Eosin Y adsorption on the MnO2@rGO nanocomposite surface is achieved in 120 min. The nanocomposite demonstrated a high dye adsorption rate due to its extensive surface area, which facilitates substantial dye uptake‏. To assess the adsorption kinetics of Eosin Y on the MnO2@rGO surface; the data suggested that the pseudo-second-order model fit the data better. The Langmuir, Freundlich, and Temkin equations are examples of linear forms of adsorption isotherms that were investigated in this study and ‎the substantial correlation coefficient for the Freundlich isotherm model suggests that the ‎adsorption of Eosin Y dye on the MnO2@rGO nanocomposite surface is multilayered. Furthermore, the effects of pH, ionic strength, and thermodynamic factors on maximum adsorption were examined. In addition, thermodynamic functions including entropy (∆S), enthalpy (∆H), and Gibbs free energy (∆G) were evaluated and the adsorption is physical. KEY WORDS: MnO2@rGO nanocomposite, Eosin yellow dye, Adsorption, Adsorption isothermal, Characterization, Thermodynamics, Kinetics Bull. Chem. Soc. Ethiop. 2025, 39(6), 1213-1226. DOI: https://dx.doi.org/10.4314/bcse.v39i6.15