Adsorption studies of Cu(II) from aqueous/acidic solutions on to bentonite

Abstract

The ability of bentonite to remove CuII from aqueous and acidic solutions at different pH values has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature and shaking time. The maximum (85%) adsorption of CuII was achieved from aqueous solution at pH 3.8. The influence of different anions and cations in the 0-1000 μg/ml concentration range on the adsorption of copper under optimized conditions has been examined. A flame atomic absorption spectrometer was used for measuring the copper concentration before and after adsorption. Isotherm analysis of the adsorption data obtained at 25 °C, 30 °C, 40 °C and 50 °C showed that the adsorption of copper(II) on bentonite could be described by both the Langmuir and the Freundlich isotherms. Values of ΔH° and ΔSDGR were calculated from the slope and intercept of the ln KD versus 1/T plots.