Adsorption studies of CuII from aqueous/acidic solutions on to bentonite

The ability of bentonite to remove Cu-II 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 Cu-II was achieved from aqueous solution at pH 3.8. The influence of different anions and cations in the 0-1000 mu g/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 degrees C, 30 degrees C, 40 degrees C and 50 degrees C showed that the adsorption of copper(II) on bentonite could be described by both the Langmuir and the Freundlich isotherms. Values of Delta H-0 and Delta S-0 were calculated from the slope and intercept of the In K-D versus 1/T plots.