Concentration of neptunium from the ground waters of the Karachai Lake contamination area

Neptunium(V) sorption from simulated and natural ground waters, containing ammonium carbonates, acetates, oxalates and citrates, on multi-walled carbon nanotubes (MWCNT) «Taunit»® was studied. It has been discovered that ammonium acetate and carbonate are not adsorbed on MWCNT «Taunit», but humic acid, oxalates and citrates are adsorbed quite efficiently. Neptunium is extracted from the ammonium carbonate solution by MWCNT «Taunit» with low sorption degrees. While conducting the sorption process from the ammonium carbonate solution with addition of organic substances, it has been revealed that the neptunium extraction degree is not dependent on addition of humic acid and acetate. At the same time, the extraction degree is substantially increased at addition of ammonium oxalate and citrate. It enables modifying MWCNT «Taunit» by means of related organic ligands and using them for the purpose of extraction and concentration of neptunium from contaminated natural waters.