Application of Sepiolite-Poly(vinylimidazole) composite for the removal of Cu(II) from aqueous solution: Isotherm and thermodynamics studies

For removal of Cu(II) ions from aqueous solution, a novel composite was prepared from 1-vinyl imidazole and sepiolite by the technique of in-situ polymerization. Adsorption of Cu(II) ions from aqueous solution onto Sepiolite-Poly(vinylimidazole) composite has been studied at 277, 298, 318, and 338 K and the experimental data were analyzed using fourteen isotherm models. The determination coefficients (R2) were determined for each isotherm analysis. The determination coefficients demonstrated that in general the accuracy of models to fit experimental data improves with the number of parameters. The Langmuir model provided the best fit to the experimental data among the two-parameter isotherms. The Toth model provided the best fit to the data among the three-parameter models. Adsorption isotherm modeling shows that the interaction of Cu(II) with Sepiolite-Poly(vinylimidazole) composite surface is localized to monolayer sorption and adsorption is an endothermic process. Additionally, adsorption experiments showed that Sepiolite-Poly(vinylimidazole) composite can be used as an effective adsorbent for the removal of Cu(II) ions from aqueous solution.