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Title: Methyl iodide sorption by reduced silver mordenite

Technical Report ·
DOI:https://doi.org/10.2172/6017408· OSTI ID:6017408

At the Pacific Northwest Laboratory (PNL), we performed two sets of experiments to determine the effects of pertinent operational parameters and gas compositions on organic radioiodine (in particular methyl iodide (CH/sub 3/I)) capture by silver mordenite (AgZ). In the first set of experiments, we studied the effects of (1) hydrogen pretreatment of AgZ, (2) change in particle size of AgZ, and (3) the presence of water in the gas phase. In the second set of experiments we evaluated on a semi-quantitative basis the effects of nitric oxide (NO), nitrogen dioxide (NO/sub 2/), superficial face velocity, and temperature on CH/sub 3/I capture by reduced (hydrogen pretreated) silver mordenite (Ag/sup 0/Z). These studies have shown that AgZ, especially Ag/sup 0/Z, is an effective trap for CH/sub 3/I. However, its effectiveness varies with changes in operational parameters and is affected by other gases found in the process off gas of a nuclear reprocessing plant. Optimum trappig efficiency was achieved with Ag/sup 0/Z rather than AgZ, 20-40 mesh Ag/sup 0/Z rather than 0.16 cm extrudate, moisture in the gas stream, higher temperatures up to 200/sup 0/C, absence of NO, and lower superficial face velocities down to 3.75 m/min. Additionally, CH/sub 3/I can be converted to elemental iodine (I/sub 2/) in the presence of NO or NO/sub 2/ by controlling the operational parameters. Since I/sub 2/ is easier to trap than organic iodides, this should improve trapping efficiency,.

Research Organization:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
6017408
Report Number(s):
PNL-4489; ON: DE83014936; TRN: 83-018828
Resource Relation:
Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English