ИСТИНА

Detonation nanodiamonds (DND) are potentially promising candidate for sorption applications due to their unique properties: high surface area, highly developed surface, low weight, chemical and radiation resistance. The oxygen-containing groups on the DND surface are responsible for the cation-exchange properties. The purpose of this work is to establish the sorption behavior of radionuclides Th(IV), U(VI), Np(V), Pu(IV) and Am(III) on DND and to investigate the effect of surface functionalization of DND on sorption properties. In our experiments different DND were used: pristine sample (ND), produced at the Special Construction-Technological Bureau "Technolog" of Saint-Petersburg State Institute of Technology (Technical University) (Russia) and two samples ND-ox and ND-red, treated with acids and hydrogen consequently. The initial ND sample was characterized by different techniques – HR-TEM, XRD and RAMAN spectroscopy. The surfaces of ND, ND-ox and ND-red were characterized by IR spectroscopy and XPS. The values of ζ-potential at different pH of the suspensions were measured using Dynamic Light Scattering. Kinetics of sorption shows that steady state conditions are achieved within first 5 minutes of interaction. The sorption is very high for U(VI), Th(IV), Am(III) and Pu(IV) even in the range of pH 1-3. To determine the sorption capacity of ND towards U(VI) cation the sorption isotherm at pH 4 was obtained. The sorption capacity is comparable to other carbon materials. U(VI) speciation was studied using time-resolved laser-induced fluorescence spectroscopy: the existence of a single fluorescent U(VI) complex sorbed onto ND surface was shown.