Preparation of graphite by thermal annealing of polyacrylamide precursor for adsorption of Cs(I) and Co(II) ions from aqueous solutions

Abstract

In the present work, graphite nanostructures are prepared by thermolysis of a prepared polyacrylamide gel. The gel was prepared by radical chain polymerization and the synthesis of the nanostructures was done by step annealing at different temperatures. The structural of the prepared materials was studied by X-ray diffraction (XRD). The presence of carboxylic and phenolic functional groups on the graphite surface was confirmed by FT-IR analysis. Batch adsorption experiments were conducted to study the effect of equilibration time, initial metal cation concentration, and solution pH for the removal of Cs(I) and Co(II) from aqueous solutions. Kinetic data of Cs(I) adsorption was found to be well fitted with a pseudo-first-order kinetic model. The obtained isotherm data were correlated with the Langumir and Freundlich isotherm models. The effect of temperature on the equilibrium distribution values was utilized to evaluate the change in the standard thermodynamic quantities of enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°).