Isotherm modeling and batch adsorber design for the adsorption of Cu(II) on a clay containing montmorillonite

Clay of the Gulbarga region, Karnataka, India, containing montmorillonite was evaluated as an adsorbent for Cu(II) from aqueous solutions. Equilibrium studies at pH 2.5 for the adsorption of Cu(II) on the clay were performed and modeling of Cu(II) adsorption on the clay was carried out with various isotherms. The Langmuir model provided the best fit to the experimental data among the two-parameter isotherms. The Langmuir monolayer adsorption capacity and the cation exchange capacity of the clay were found to be about 31 mg Cu(II)/g and 86 meq/100 g respectively. The Fritz–Schluender model provided the best fit to the data among the three-parameter models. A two-stage batch adsorber was designed for the removal of Cu(II) from aqueous solutions, which reduced the adsorbent dose by 51% when compared to that of a single-stage adsorption system.

Research Highlights
► Clay of Gulbarga region, Karnataka, India was evaluated as adsorbent for Cu(II).
► Fritz-Schluender adsorption isotherm gave the best fit to the experimental data.
► Langmuir adsorption capacity of the clay was found to be 31 mg Cu(II)/g.
► Cation exchange capacity of the clay was found to be 86 meq/100 g.
► Two-stage adsorber reduced the clay dose by 51%.