Reactions of iodine and iodate with sphagnum peat: An examination of kinetics and pH dependence
Master of Science (MS)
First Committee Member
Number of Pages
Storage of spent nuclear waste is an environmental and industrial concern that must be addressed. Iodine-129, a by-product of nuclear waste reprocessing, has a strong environmental presence with a half live of 15.7 million years. Radioactive iodine is currently immobilized by carbon-containing materials and silver impregnated materials. In this research, sphagnum peat was examined as a material to sequester iodine. Several analytical methods were used to determine the ability of sphagnum peat to sequester iodine. The kinetics of the reaction between sphagnum peat and iodine were also examined; Solid phase microextraction was used to determine the peat's ability to retain volatile and slightly volatile iodinated compounds. A carboxen/PDMS fiber was a more suitable fiber for the analysis compared to a PDMS and Carbowax-DVB fiber. Diiodimethane, methyl iodide, iodoethene, chloroiodimethane, triiodimethane were detected in trace quantities for a sample that had a 15 hour carboxen/PDMS fiber equilibration time in a Ca(OH)2 matrix; The reaction of iodine with sphagnum peat was dependent on pH. At pH 4.7, 100% of the iodine was substituted on the phenolic ring compounds in the peat. At pH 5.8 the 66% of the iodine underwent ring substitution, and 60% at pH 8. At pH 10, the reaction kinetics was too fast to examine by the method used; The reaction of iodate with peat was also controlled by pH. The rate constant k, for the reaction decreased as pH increased.
Dependence; Examination; Iodate; Iodine; Kinetics; Peat; Ph; Reactions; Sphagnum
Chemistry, Analytic; Radiation chemistry
University of Nevada, Las Vegas
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Kimble, Ginger Marie, "Reactions of iodine and iodate with sphagnum peat: An examination of kinetics and pH dependence" (2008). UNLV Retrospective Theses & Dissertations. 2440.
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