Peanut shells and talc powder for removal of hexavalent chromium from aqueous solutions

In this work, talc powder and peanut shells were investigated as potential adsorbents for the removal of hexavalent chromium from aqueous solutions. The effect of important parameters, such as contact time, solution pH and adsorbent dosage were also evaluated for the adsorption process of chromium (IV). The experimental data showed that a contact time of 30 min for peanut shells and 70 min for talc powder and pH of 4 were optimum for the adsorption to reach equilibrium. Furthermore, FT-IR, SEM and BET measurements were made in order to assess the physicochemical properties of the substrates. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were used to fit the equilibrium data, heat and energy of adsorption of both adsorbents. Determinations of the rate of adsorption using kinetic models follow pseudo-first order for peanut shells and talc powder with intraparticle diffusion.