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Isotope Exchange and Fractionation Corrections for Extraction of Tritiated Water in Silica Gel by Freeze-Drying Techniques.

DE200515013462

Publication Date	2001
Personal Author	Guthrie, E. B.; Shen, N. C.; Bandong, B. B.
Page Count	16
Abstract	A concentration correction curve was established for measuring the activity concentration of airborne tritiated water collected with dried silica gel and extracted by the LLNL Environmental Monitoring Radiological Laboratory freeze-dry technique. A tracer study using standard tritiated water with silica gel showed that the concentration of tritium in the extracted water is lower than that in the adsorbed water by a fraction proportional to the amount of adsorbed water. The observed decrease in tritium concentration in the extracted water can be accounted for by dilution due to isotopic exchange with both nontritiated water and hydroxyl groups within the silica gel matrix. For the range of 8 - 35% adsorbed water, which is typical of samples collected in LLNL monitoring stations, the derived exchangeable water in the silica gel material under investigation was (5.12 - 0.08) %. The contribution of the H(sub 2)O/HTO vapor pressure effect using published empirical data in the literature was also considered in calculating the degree of isotopic exchange.
Keywords	Tritiated water Silica gel Freeze drying Tritium Extraction Isotope exchange Hydroxy groups Sampling Monitoring stations Fractionation Lawrence Livermore National laboratory (LLNL)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200602

Isotope Exchange and Fractionation Corrections for Extraction of Tritiated Water in Silica Gel by Freeze-Drying Techniques.

Isotope Exchange and Fractionation Corrections for Extraction of Tritiated Water in Silica Gel by Freeze-Drying Techniques.
DE200515013462

Publication Date	2001
Personal Author	Guthrie, E. B.; Shen, N. C.; Bandong, B. B.
Page Count	16
Abstract	A concentration correction curve was established for measuring the activity concentration of airborne tritiated water collected with dried silica gel and extracted by the LLNL Environmental Monitoring Radiological Laboratory freeze-dry technique. A tracer study using standard tritiated water with silica gel showed that the concentration of tritium in the extracted water is lower than that in the adsorbed water by a fraction proportional to the amount of adsorbed water. The observed decrease in tritium concentration in the extracted water can be accounted for by dilution due to isotopic exchange with both nontritiated water and hydroxyl groups within the silica gel matrix. For the range of 8 - 35% adsorbed water, which is typical of samples collected in LLNL monitoring stations, the derived exchangeable water in the silica gel material under investigation was (5.12 - 0.08) %. The contribution of the H(sub 2)O/HTO vapor pressure effect using published empirical data in the literature was also considered in calculating the degree of isotopic exchange.
Keywords	Tritiated water Silica gel Freeze drying Tritium Extraction Isotope exchange Hydroxy groups Sampling Monitoring stations Fractionation Lawrence Livermore National laboratory (LLNL)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200602