In this article, a series of batch experiments were carried out to investigate the effect of various environmental factors
such as contact time, solid content, pH, ionic strength, foreign ions, temperature and coexisting humic acid on the sorption
behavior radionuclide 60Co(II) on illite. The results indicated that the sorption of Co(II) was strongly dependent on pH, ionic strength and temperature.
At low pH, the sorption was dominated by outer-sphere surface complexation and ion exchange on illite surfaces, whereas inner-sphere
surface complexation was the main sorption mechanism at high pH. The Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models
were used to simulate the sorption isotherms at three different temperatures of 303.15, 323.15 and 343.15 K. The thermodynamic
data (∆G0, ∆S0, ∆H0) were calculated from the temperature dependent sorption isotherms and the results suggested that the sorption process of
Co(II) on illite was an endothermic and spontaneous process. The sorption test revealed that the illite can be as a cost-effective
adsorbent suitable for pre-concentration of Co(II) from large volumes of aqueous solutions.