Mechanochemical Treated Multi-walled Carbon Nanotubes for Incorporation of Metal Ions

Ni catalyst was removed from as received multi-walled Carbon Nanotubes (MWNTs) by acid treatment. Then, the nanotubes were treated with 4M HCl during a ball milling processing yielding mechanochemical treated MWNTs (mech-MWNT's). TEM micrographs indicate that the mech-MWNTs were still of a tubular form but with much shorter length. The equilibrium adsorption of metal ions, e.g Cu2+ and Ni2+, on the mech-MWNTs was investigated at room temperature. The adsorption isotherms gave excellent consistence with the Langmuir theory and the best fit values of K-1 and N-max can be evaluated using non-linear least-squares. As results, the maximum of Cu2+ and Ni2+ ions uptake on to the mech-MWNTs are 0.93 +/- 0.004 mg/g and 2.11 +/- 0.01 mg/g respectively. There is no evidence indicating that the pore structure and layer Surfaces at both ends of the mech-MWNTs are appropriate sites for metal ions adsorption.