Application of Kinetic and isotherm models to the Sorption of Copper (II) on to superabsorbent polymer in powder form

Abstract

Equlibrium sorption of the sodium polyacrylate (PANa) in powder form was studied. The Elovich model and the Pseudo-second order model both provided a high degree of correlation with the experimental data for most of the sorption process. The equilibrium sorption data were also fitted into Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D-R) isotherms. Of the four adsorption isotherms, the R 2 value of Langmuir isotherm model was the highest. The maximum monolayer coverage (q m ) from Langmuir isotherm model was determined to be 116.8 mg/g, the separation factor indicating a favorable sorption experiment is 0<R L <0.35. Also from Freundlich isotherm model, the sorption intensity (n) which indicates favorable sorption and the correlation value are 2.44 and 0.91 respectively. The heat of sorption process was estimated from Temkin Isotherm model to be 139.52 KJ/mol and the mean free energy was estimated from D-R isotherm model to be 2236 KJ/mol which vividly proved that the adsorption experiment followed a chemical process.