Hydrothermal synthesis of magnetic CoFe2O4 nanoparticles and CoFe2O4/MWCNTs nanocomposites for U and Pb removal from aqueous solutions

Magnetite CoFe2O4 nanoparticle and CoFe2O4/MWCNT nanocomposite adsorbents with high specific surface area, high adsorption capacity, and easily separable property were synthesized by the hydrothermal method for uranium and lead removal from aqueous solutions. The synthesized samples were characterized by FT-IR, XRD, SEM, and BET analysis. The estimated specific surface areas were obtained as 113.4 and 186.1 m(2) g(-1) for CoFe2O4 and CoFe2O4/MWCNTs, respectively. The synthesized nanostructures resulted in achieving the maximum monolayer adsorption capacity. The adsorption capacity of U(VI) and Pb(II) onto CoFe2O4 nanoparticles and CoFe2O4/MWCNT nanocomposites were obtained as 294.12 (at pH 5) and 500 mg g(-1) (at pH 6) for uranium and 109.89 and 217.39 mg g(-1) for lead (at pH 5), respectively, which indicated the favorable effects of decorated MWCNT on the removal of uranium and lead. Several parameters, including pH, contact time, initial U(VI) concentration and solution volume, and adsorbent concentration, which influence the adsorption capacity, were also investigated.