Plasma Induced Multiwalled Carbon Nanotube Grafted with 2-Vinylpyridine for Preconcentration of Pb(II) from Aqueous Solutions

Multiwalled carbon nanotubes (MWCNTs) are grafted with 2-vinylpyridine (VP) by using N-2 plasma technique. The VP grafted MWCNTs (MWCNT-g-VP) are characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, and thermo-gravimetric analysis-differential thermal analysis. The application of MWCNTs and MWCNT-g-VP in the removal of Pb(II) from large volumes of wastewater is investigated under ambient conditions. The results indicate that the grafted VP improved MWCNT sorption capacity obviously in the removal of Pb(II). The VP molecules grafted on the surfaces of MWCNT-g-VP can prevent the entanglement of MWCNT-g-VP and provide more functional groups, promoting the sorption of Pb(II) onto MWCNT-g-VP. According to the results simulated by Langmuir model, the maximum sorption capacities (C-smax) of Pb(II) are similar to 15.9mg.g(-1) on MWCNTs and similar to 37.0mg.g(-1) on MWCNT-g-VP at pH = 6.0. The variation of separation factors indicates that the sorption of Pb(II) on MWCNTs and MWCNT-g-VP is favorable. The relatively high sorption capacity shows that MWCNT-g-VP is a suitable material for the preconcentration and immobilization of heavy metal ions from large volumes of aqueous solutions in environmental pollution management.