Adsorptive removal of chromium(VI) from aqueous solution unto groundnut shell

Chromium present in high levels in water poses a serious problem in many places around the world, sometimes in relation to natural sources and in other cases to anthropogenic ones. Adsorption process using natural materials is among the most effective techniques for removing many heavy metal ions from different types of water sources. In the present study, groundnut shell was used as a nonconventional adsorbent for effective removal of chromium(VI) from aqueous solutions using batch experiments. The adsorption of chromium(VI) unto groundnut shells was found to be dependent on contact time, pH, adsorbent dose, initial concentration and temperature. The adsorption of Cr(VI) was found to be optimum at a contact time of 120 min, pH 8.0, an adsorbent dose of 2.0 g/L, initial metal ion concentration of 25 mg/L and temperature of 41.5 °C. The experimental data were analyzed using three two-parameter isotherm models. The experimental data obtained for the adsorption of chromium(VI) ion fitted well to Temkin isotherm in comparison with the other isotherm models tested.