Abstract: Multi-walled carbon nanotubes(MWCNTs) were modified with 2-vinylpyridine (VP) by using N₂ plasma technique. The application of MWCNTs-g-VP in the preconcentration of ⁶⁰Co(Ⅱ) from large volumes of wastewater was investigated under ambient conditions. The results indicate that the VP molecules grafted on the surfaces of MWCNTs-g-VP can prevent the entanglement of MWCNTs and provide more functional groups, promoting the sorption of ⁶⁰Co(Ⅱ) on MWCNTs-g-VP. The preconcentration of ⁶⁰Co(Ⅱ) on MWCNTs-g-VP is strongly dependent on pH values and ionic strength, suggesting that inner sphere complexation and outer-sphere complexation are the preconcentration mechanisms. According to the results simulated by Langmuir model, the maximum sorption capacities (C_max) of ⁶⁰Co(Ⅱ) are 13.9 mg/g on MWCNTs-g-VP at pH=7.5. The relatively high sorption capacity shows that MWCNTs-g-VP is a suitable material for the preconcentration and immobilization of radionuclides from large volumes of aqueous solutions in environmental pollution treatment.