Comparative Analysis and Speciation of Sulfur K, L-edge X-ray Absorption Spectroscopy
Date
2024-09-25
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
Sulfur plays a critical role in the evolution of many common biological aspects of life as a key component of protein and enzyme function. It also plays a significant role in the contemporary demand for energy resources in modern society, with associated industrial and commercial applications. Sulfur composes a complex variety of organic and inorganic compounds and are naturally occurring in many hydrocarbon bearing reservoirs and other mineral resources. These energy and mineral resources are critical for industrial and technological development. Some of these sulfur compounds may have critical impacts on materials used in the transportation and refining of hydrocarbon products. These compounds also impact steam generated power infrastructure such as those found in pressurized water reactors. The characterization of sulfur, which has a formal oxidation state ranging from -2 to +6, using K-edge X-ray absorption spectroscopy is particularly useful for determining oxidized species. There are, however, limitations on the ability to visually resolve spectra for reduced and mixed sulfur compounds using the K-edge that may be better resolved using the L-edge due in part to an increase in photon resolution and chemical sensitivity at lower energy. A qualitative and quantitative study was completed on a broad spectrum of model organic and inorganic Sulfur (S) compounds using high resolution (≤0.1 eV) S K, L-edge X-ray absorption spectroscopy (XAS). All the recorded spectra for both K, L-edges were measured in fluorescence yield (TFY) and total electron yield (TEY) and only TEY were considered for the purpose of this study. A direct qualitative approach was used to directly compare the spectroscopic uniqueness and usefulness between the two absorption edges. While using S L-edge XAS may provide a more effective way to visually speciate some chemical forms of sulfur, a combined approach utilizing both Sulfur L, K-edge XAS provides a full spectrum solution to chemical speciation.
Description
Keywords
X-Ray Absorption Spectroscopy, organic sulfur, XANES
Citation
Degree
Master of Science (M.Sc.)
Department
Geological Sciences
Program
Geology