Selective Membrane Complexation and Uranium Isotopes Analysis in Tap Water and Seawater Samples

The complexation of ²³⁸U and ²³⁴U in tap water and seawater after the use of a selective membrane was examined. At the first step, many ligands were used for original membranes preparation and their yields in uranium analysis were evaluated by X-ray fluorescence, in order to select the ligand with the highest uranium selectivity in water samples. At the second step the new prepared membrane was used for uranium analysis by α-spectrometry. Various factors were tested for a more effective uranium binding such as a membrane's active surface, water sample volume, equilibration time, and stirring during the process. After membrane complexation, uranium was separated by anion exchange and electroplated onto stainless steel plates in order to prepare suitable α-ray sources; these sources were measured by α-spectrometry and gave high chemical uranium recoveries and very good energy resolution spectra. The method can successfully be applied even for relatively small sample volumes and seawater samples.