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.