Contribution to the removal study of Co2+ ions by acid-activated clay from Maghnia (Algeria): equilibrium and kinetic studies

A sample of clay, bentonite from Maghnia (N.W. Algeria) was treated (acid-activated) and used as adsorbent for the removal of Co2+ ions from aqueous solutions. The effect of acid treatment, shaking time, pH of aqueous solution, metal concentration and adsorbent amount was studied. The sorption kinetics of Co2+ have been analysed by Lagergren pseudo-first order and pseudo-second order kinetic models. The experimental results indicated that the best fit is obtained with the pseudo-second order kinetic model. The experimental equilibrium adsorption data were tested for the Freundlich and Langmuir equations. Results indicate that the order fit is Freundlich > Langmuir.