Files and links (1)
Ramin_Ordikhani_Dissertation_0501202310.76 MB
Embargoed Access, Embargo ends: 06/30/2027
Dissertation
A study of interfacial molecular interactions and surface behavior by electrochemistry, spectroscopy, and surface characterization techniques
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2023
DOI: 10.25820/etd.007056
Abstract
Interfacial chemistry and surface chemistry study chemical interactions and phenomena occurring at the interfaces or surfaces of materials. A material's surface is the region that separates its bulk from its surroundings. An interfacial region is the boundary or region between two different kinds of materials or phases. Typically, these regions are between a few nanometers or a few micrometers in size. Surface properties of solids, liquids, and gases are studied in this field, as well as chemical adsorption and desorption. Intermolecular forces such as London dispersion forces, dipole-dipole interactions, hydrogen bonds, and ion-dipole interactions play an important role in surface chemistry and interfacial chemistry. Through a variety of approaches, this dissertation examines the surface characteristics of materials and explores the interactions taking place in the interfacial thin layer. The intricate nature of these interfaces was investigated using spectroscopic, microscopic, and electrochemical techniques in this dissertation.
The first part of the dissertation examines the surface characteristics of materials and their wetting behavior. The dissertation uses surface characterization and spectroscopy techniques to study the surface morphology, topography, and surface chemistry of synthesized metal parts, focusing on the factors affecting superhydrophobicity and surface adhesion. With contact angle measurements, the results reveal that chemical treatment and surface texturing contribute to superhydrophobicity. Various chemical modification techniques have been used to create superhydrophobic properties on metal surfaces. Among these, extended exposure to ambient air is one of the most popular options, however it can take days if not months. This process is shortened to a few hours by our work, along with the use of chemical reagents in optimum concentrations for metal coating.
In the second part of the dissertation, a pyrometallurgical approach is developed to gasify electronic waste and recycle coinage metals and rare earth metals using biomass fuel. Using a gasifier, the study is conducted to determine whether metals can be extracted from nodules on the surface of biochar under different experimental conditions. Different surface characterization techniques such as SEM and EDS along with XRF to determine the metal nodule compositions on biochar surfaces. The largest surface nodules are created when an oxidizing atmosphere with N2+O2 is followed by a reducing atmosphere with N2+H2. Instead of relying on chemicals to separate and extract these metal pieces from electronic waste, physical methods can be used.
Finally, a spectroelectrochemical cell is designed to conduct in-situ spectroelectrochemical measurements on the electrode-electrolyte interface. The main objective of this part of dissertation is to investigate how electrodes interact with nitrobenzene, which is a suitable anolyte for redox flow batteries because of its electrochemical reversibility and negative redox potential. The dissertation investigates nitrobenzene behavior on the surface using in-situ reflective infrared measurements and electrochemical measurements, with a particular focus on the orientational changes of nitrobenzene during the redox reaction on the surface.
Overall, this dissertation offers a comprehensive overview of surface and interfacial chemistry, focusing on how spectroscopy, microscopy, and electrochemistry may improve our understanding of these interfaces.
Details
- Title: Subtitle
- A study of interfacial molecular interactions and surface behavior by electrochemistry, spectroscopy, and surface characterization techniques
- Creators
- Ramin Ordikhani Seyedlar
- Contributors
- Scott K Shaw (Advisor)Scott Daly (Committee Member)Johna Leddy (Committee Member)Mark A Arnold (Committee Member)Hongtao Ding (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Chemistry
- Date degree season
- Spring 2023
- Publisher
- University of Iowa
- DOI
- 10.25820/etd.007056
- Number of pages
- xx, 238 pages
- Copyright
- Copyright 2023 Ramin Ordikhani Seyedlar
- Language
- English
- Date submitted
- 04/25/2023
- Date approved
- 06/30/2023
- Description illustrations
- illustrations, tables, graphs
- Description bibliographic
- Includes bibliographical references (pages 225-238).
- Public Abstract (ETD)
- Surface chemistry and interfacial chemistry study chemical interactions and surface phenomena. A surface is the outermost layer of a substance, while an interface is the junction of two phases. When rain falls on a car window, there is a solid-liquid phase. This dissertation provides insight into how surface chemistry can be used in different applications and how to gain deeper insight into what happens on surfaces, especially very thin interfacial layers. In the interfacial region, molecules behave differently than in the bulk. Intermolecular forces that each atom feels in the bulk are very different from those felt by the outermost surface layers of atoms. Surface behavior is very much determined by the chemistry and structure of the surface. When wetted, surface structure, and adsorbed molecules can determine whether a surface is hydrophobic (repels water) or hydrophilic (attracts water). The results of this research indicate that creating micro-sized channels on metal surfaces and treating them with fluorine-containing chemicals can increase their water-repellent behavior. In the second part of this dissertation, surface chemistry techniques were used to study the surface of biochar (biochar is a charcoal-like material made from decomposing plant materials at high temperatures) to recycle strategic metals that are used in most electronic devices and are considered critical metals (rare earth metals). In the final part of this dissertation, surface chemistry spectroscopic techniques were used along with electrochemistry techniques to understand the interfacial layer on battery electrodes. We investigated how energy active materials in conductive solutions (electrolytes) behave at the interface and while undergoing electrochemical reactions. As a result of the research presented in this dissertation, new materials and techniques can be developed that will better meet the demands of modern industry and research.
- Academic Unit
- Chemistry
- Record Identifier
- 9984425198802771
Metrics
28 Record Views