By a News Reporter-Staff News Editor at Science Letter -- Research findings on Radiochemistry are discussed in a new report. According to news reporting originating in Mainz, Germany, by NewsRx journalists, research stated, "Continuous liquid-liquid extraction of short-lived radionuclides has traditionally been performed with the SISAK system consisting of static mixers and H-centrifuges for phase separation. SISAK operates at flow rates of typically 1 mL/s."
The news reporters obtained a quote from the research from Helmholtz Institute, "Thus, it produces large volumes of radioactive liquid waste that is difficult to dispose of. Therefore, it has been aimed to develop and use a further miniaturised extraction unit based on microtechnology and precision engineering to reduce the flow rate by at least two orders of magnitude. The accordingly developed MicroSISAK device is a micro membrane extractor in which a micromixer element with 2 x 16 feed channels of 30 mu m width followed by a 60 mu m high mixing chamber is used for intimately contacting the aqueous and organic phase. Subsequent phase separation is achieved via hydrophobic Teflon membranes with a pore size of 1 mu m. The MicroSISAK device has been tested and optimized with radiotracers of the group-4 elements Zr and Hf in the system H2SO4/trioctyl amine (TOA) in toluene. At a temperature of 58 degrees C and a flow rate of 0.2 mL/min of both phases, extraction yields of 87 +/- 3% were achieved. The transport time from the micromixer to the first Teflon membrane was in this case 3.9 s. It can be shortened to 1.56 s at a flow rate of 0.5 mL/min. Under similar conditions, the extraction yield of Tc-99m milked from a Mo-99 generator in the system HNO3/tetraphenyl arsonium chloride (TPAC) in chloroform was 83 +/- 3%. In an on-line experiment at the TRIGA Mainz reactor, short-lived Tc isotopes produced in the fission of U-235 with thermal neutrons were transported by a He/KCl gas-jet to the chemistry apparatus, deposited by impaction, dissolved in 0.01 mol/L HNO3/KBrO3, and extracted into 10(-4) mol/L TPAC in chloroform in MicroSISAK. The separated phases were transported via capillaries to two separate flow-through cells positioned in front of two Ge detectors. The extraction yield determined as the ratio of the Tc gamma-ray activities in both detectors was 76 +/- 1%. With this experiment, it was demonstrated that MicroSISAK is in principle ready for an on-line experiment for the chemical characterization of the superheavy element bohrium, element 107."
According to the news reporters, the research concluded: "However, the detection of alpha-particle activities by liquid scintillation counting still needs to be worked out."
For more information on this research see: MicroSISAK: continuous liquid-liquid extractions of radionuclides at >= 0.2 mL/min. Radiochimica Acta, 2013;101(11):681-689. Radiochimica Acta can be contacted at: Walter De Gruyter Gmbh, Genthiner Strasse 13, D-10785 Berlin, Germany (see also Radiochemistry).
Our news correspondents report that additional information may be obtained by contacting D. Hild, Helmholtz Inst Mainz, D-55099 Mainz, Germany. Additional authors for this research include K. Eberhardt, J. Even, J.V. Kratz, N. Wiehl, P. Lob, B. Werner and C. Hofmann.
Keywords for this news article include: Mainz, Europe, Germany, Radiochemistry
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