Thermodynamic studies of Ni(II) adsorption onto bentonite from aqueous solution

The adsorption behavior of Ni(II) onto bentonite was studied as a function of temperature under optimized conditions of shaking time, amount of adsorbent, pH, and concentration of the adsorbate. Thermodynamic parameters such as ΔH∘, ΔS∘, and ΔG∘ were calculated from the slope and intercept of the linear plot of lgKD against 1/T. Analysis of adsorption results obtained at T=(298, 303, 313, and 323) K showed that the adsorption pattern on bentonite followed the Langmuir, Freundlich, and D–R isotherms. A flame atomic absorption spectrophotometer was used for measuring the concentration of Ni(II).