Award Date

1-1-2005

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Committee Member

Dennis W. Lindle

Number of Pages

63

Abstract

Proliferation of nuclear waste is a major environmental issue we all face this century. Long lived radioactive isotopes such as 90Sr contained in spent nuclear fuel have been causing major problems during the disposal stage of the nuclear fuel cycle. Disposal of radioactive isotopes requires a suitable confinement host material in order to dispose of them in a safe and appropriate repository. In this thesis I describe how to synthesize and characterize the mineral fluorapatite as a host material for Sr. Fluorapatite is a naturally occurring mineral with the unit cell formula of Ca10(PO 4)6F2. This mineral possesses a stable hexagonal crystal structure and has the natural ability to accommodate foreign cations in its structure; Pure fluorapatite and varying amounts of strontium-bearing fluorapatite were synthesized by using wet chemical synthesis methods. Products of the synthesis were confirmed by using x-ray powder diffraction analysis. Increasing lattice dimensions were observed with increasing strontium concentration. The hydroxyl stretching band in the infrared spectra further established the formation of fluorapatite in all synthetic products. It was observed that the strontium substitutions at the Ca sites have influenced the hydroxyl stretching frequency of strontium containing fluorapatite samples. The stretching and bending modes of the phosphate groups have also been slightly affected by Sr2+ insertion but have not changed the basic fluorapatite structure. SEM images of the annealed fluorapatite samples also verify the formation of hexagonal crystals.

Keywords

Characterization; Fluorapatite; Strontium; Synthesis

Controlled Subject

Chemistry, Physical and theoretical; Chemistry, Inorganic; Nuclear chemistry

File Format

pdf

File Size

1689.6 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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