Efficient removal of Co(II) metal ion from aqueous solution using cost-effective oxidized activated carbon: kinetic and isotherm studies.

Oxidized activated carbon (OAC) was prepared from a waste mixture containing palm stem, paper, and plastic and used for the removal of Co(II) from aqueous medium. Adsorption was studied as a function of OAC dose (0.03-0.1 g), time (10-180 min), pH (2-6) and initial Co(II) concentration (50 mg L^-1). The maximum adsorption capacity was found 83.6 mg g^-1 at pH 4. The adsorption process followed the Freundlich isotherm model and pseudo-second-order kinetics. The OAC showed better efficiency comparable with other reported adsorbents. The results suggested that the prepared OAC could be used as a cost-effective adsorbent for the Co(II) removal from aqueous solutions. [ABSTRACT FROM AUTHOR]