Equilibrium,kinetic and thermodynamic studies of copper adsorption onto poly(n-vinylpyrrolidone) modified clay

We demonstrated in this study the removal of copper ions from aqueous solutions by a new and cost efficiency adsorbent based on poly(N-vinylpyrrolidone) modified sodium bentonite. The X-ray diffraction analysis confirmed that the poly(N-vinylpyrrolidone) is well intercalated in the clay inter-sheets. Adsorption of copper was analyzed by the atomic absorption spectroscopy technical.

Quantitative removal of copper in aqueous solution and the optimum conditions in batch experimental set-up were attained by following searching effects such as contact time, initial metal concentration, pH and temperature.

The elimination of this pollutant by this a new composite reached 3.27 mg.g^?1, which is more important than the amount of copper adsorbed by the non-modified clay (1.5 mg.g^?1). The experimental results showed that the equilibrium and shaking time was attained within 05 min. The better retention capacity of copper was obtained at pH between 4 and 5.8.

Equilibrium data were well fitted with the Langmuir, Freundlich and Elovich models.

Also, the pseudo first order and pseudo-second-order were also applied. The experimental data follow well the pseudo-second-order kinetics. The thermodynamic of this new adsorbent of copper shows spontaneous and exothermic process with a negative value of ΔS.