Amidoxime-grafted multiwalled carbon nanotubes by plasma techniques for efficient removal of uranium(VI)

A novel solid-phase extractant, amidoxime-grafted multiwalled carbon nanotubes (AO-g-MWCNTs), has been synthesized using plasma techniques to selectively separate uranium from nuclear industrial effluents. The adsorbent was characterized by Fourier transform infrared spectra (FT-IR), elemental analysis, Raman, scanning electron microscopy (SEM), and thermal gravity analysis (TGA). Sorption behaviors of uranium(VI) on AO-g-MWCNTs were investigated by varying pH, contact time, initial uranium concentration, and temperature. An optimum sorption capacity of 145   mg   g −1 (0.61   mmol   g −1 ) for U(VI) was obtained at pH 4.5. X-ray photoelectron spectroscopy (XPS) has been used to explore the sorption mechanism of U(VI) on AO-g-MWCNTs. Furthermore, AO-g-MWCNTs could selectively adsorb U(VI) in aqueous solution containing co-existing ions (Mn 2+ , Co 2+ , Ni 2+ , Zn 2+ , Sr 2+ , Ba 2+ and Cs + ). This study shows that AO-g-MWCNTs are potential adsorbent for effective removal of U(VI) from aqueous solution.