M. Tanaka

M. Tokeshi

R. Hazama

Y. Ogata

Y. Sakuma

National Institute for Fusion Science (NIFS-Repository)

Development of �TAS System for Remove of Tritium and Isotope SeparationHazama, R. (Hiroshima Univ.) Sakuma, Y. (Tokyo Inst. Tech.), Tanaka, M., Ogata, Y., Tokeshi, M. (Nagoya Univ.)      Tritium is produced by the side reaction of18O(p,t)16O during the production of PET-FDG([18F]-2-fluoro-2-deoxy-D-glucose). Several processes for thetritium separation have been developed, e.g., distillation,chemical exchange, catalytic exchange, and electrolysis. 1)The chemical exchange utilizing microchannel chip is totally a brand-new technique and had the advantage of fastand high conversion phase-transfer synthesis exploiting the liquid-gas(liquid) interface formed in a microchannel chip.2) Simple introduction of two phases into the microchannelprovided a stable liquid-gas(liquid) interface, and the large specific interfacial area and short molecular diffusiondistances had a higher conversion than those of anymacroscale reaction with strong stirring. Microreactor system is superior to normal batch systems not only for ahigh conversion close to 100 %, but also for a fast reaction time less than a few seconds. The liquid-gas two phases-transfer occurs accordingto the following exchange reaction: ???????????????????????????�???????????????????????????, (1)?where we can treat HT gas rather than severely retrainedHTO liquid making use of molecular tritium and isotopeexchange reaction.      First, we tested D2O liquid in eq. (2) instead of HTOliquid in eq. (1) for ease of handling and measuring of itsconcentration in the phase-transfer reaction.????????????????????????????�???????????????????????????, (2)?     The experiment system of a microreactor isillustrated in Fig. 1. The microreactor has depths of 90 �m and 22 �m, widths of 194 �m and 64 �m, for gas phase and liquid phase, respectively, and a liquid-gascontact length of 20 mm. The reaction was performed byintroducing a D2O liquid and a H2 gas through the two-inlets of the microreactor under continuous flow conditions at ambient temperature. The concentration of D2O was measured by the density meter (Anon Paar DMA 5000M,which is the most accurate density meter on the market).The accuracy is 0.000005 g/cm3. Next, we examined the effect of the flow rate on liquid phase for the meanresidence time of 0.2 or 4 sec (9.65 �l/min for 0.2 sec and 0.57 � l/min for 4 sec). In both cases, the reactions proceeded smoothly to afford the phase-transfer of deuterium. As comparison, the flow rate reduction to about6 % is effective to increase the reaction yield of about 1 % to 3 %, which are summarized in Table. I. It is noted that the current flow rate will require a hundred minutes to a day to process one ml amount and we are planning toutilize microreactor with patterned surfaces featuring the hydrophilic and hydrophobic and fabrication of a piling-up for the next step.      Thus, the application of recent advances inmicrochip technology to our liquid-gas extraction byutilizing circulated liquid-gas multi phase flow in a microchannel chip without any stirring will be quiteattractive and can be also applied for chemical separationof the other isotopes, such as calcium. 3)Fig. 1.  Flow chart of Experimental Device.Microreactor contains deep (90 �m depth and 194 �m width) and shallow (22 �m depth and 64�mwidth) channel areas for gas phase and liquid phase,respectively.H2(gas) flow rate (cc/min) 2.3 2.3D216O flow rate (�l/min) 9.65 0.57D216O density  prior (g/cm3) 1.105276 1.105276              post (g/cm3) 1.104303 1.101427D216O concentration prior (%) 99.844 99.844                 post (%) 98.937 96.254Table. I. Reaction yield and the effect of the flow-rate on liquid phase for the liquid(D2O)-gas(H2) two phase transfer reaction. 1)  Ogata, Y. et al.: J. Radioanal. Nucl. Chem. 255(2003) 539 2) Hisamoto, H. et al.: Chem Commun. (2001) 2662 3) Hazama, R. et al.: Proc. of 6th Rencontres du Vietnam,Gioi Publishers (2007) 383: arXiv:0710.3840.[nucl-ex]473§9. evelopment of mTAS System for emove of Tritium and Isotope SeparationHazama, R. (Hiroshima Univ.),  Sakuma, Y. (Tokyo Inst. Tech.), Tanaka, M.,  Ogata, Y., Tokeshi, M. (Nagoya Univ.)

Development of μTAS System for Remove of Tritium and Isotope Separation

Abstract

Similar works

Full text

Available Versions

National Institute for Fusion Science (NIFS-Repository)