Award Date

1-1-2008

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Committee Member

Spencer Steinberg

Number of Pages

61

Abstract

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.

Keywords

Dependence; Examination; Iodate; Iodine; Kinetics; Peat; Ph; Reactions; Sphagnum

Controlled Subject

Chemistry, Analytic; Radiation chemistry

File Format

pdf

File Size

1105.92 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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