Poly amidoxime functionalized carbon nanotube as an efficient adsorbent for removal of uranium from aqueous solution

Abstract

The poly amidoxime functionalized carbon nanotube (PAO@CNT) was prepared, characterized, and applied for the adsorption of uranium from aqueous solutions. In this paper, a new preparation method of amidoxime-derived adsorbent was proposed to overcome the shortcomings of the rational design and synthesis of amidoxime-based adsorbents, which resulted in a low adsorption capacity. The homogeneous reaction and nano-skeleton support strategy were utilized to create amidoxime-rich polymer and its remold on the surface of carbon nanotube, composing the porous adsorbent. The results showed that PAO@CNT was an efficient adsorbent for uranium adsorption due to its abundant amidoxime functional group, and the adsorption capacity towards uranyl ions was significantly enhanced with the sequential improvement. With abundant chelating groups and porous structure (SBET = 58.169 m2/g), the adsorbent had a high adsorption capacity (~247 mg/g at pH = 4) and kinetics (equilibrium time: 120 min) for uranyl ions. The XPS and FT-IR spectra revealed the participation of N and O atoms of amidoxime groups in the adsorption of uranyl ions.