Sorption of U(VI) Ions on Nanocomposites Based on Zirconium Compounds Containing Partially Unzipped Carbon Nanotubes. Effect of the Solution Concentration and Temperature

Use of weapon containing depleted uranium causes pollution of environment with U(VI) compounds. In this chapter, the composites for removal of these contaminants are reported. The composites are based on hydrated zirconium dioxide and zirconium hydrophosphate, to which 2 wt% of partially unzipped carbon nanotubes were added. The nanotubes were unzipped electrochemically in the solution of sulphuric acid. The materials were investigated with the methods of X-ray analysis, transmission electron microscopy, nitrogen adsorption and FTIR spectroscopy. Specific surface area of the composites was estimated as 220–310 m2g−1, oxygen-containing groups, particularly carboxyl fragments were found for carbon material. Sorption was carried out in neutral media at 18–30 °C, the concentration of uranium was 5–75 mg dm−3. It is possible to remove U(VI) from water completely at 30° in 4 h using composites. Despite low content of unzipped nanotubes, they increase sorption capacity of inorganic materials practically in 2 times in the field of low concentration, where their effect is most expressed. The rate of sorption obeys a model of first order, carbon additions decrease activation energy. Regeneration of sorbents with a Trilon B solution was investigated.