- Research Group
- Research Interests
steven higgins, ph.d. - student & postdoc opportunities
Research Projects in Analytical, Environmental, and Physical Chemistry for Undergraduate Students
Crystal Growth and Dissolution: This project aims to understand molecular-level inorganic and bio-mineralization processes that influence the chemistry of our Earth’s environment. While it is advantageous to make the assumption that most of Earth’s chemical processes are in a state of equilibrium, this assumption is often invalid due to slow chemical kinetics at solid-liquid
BaSO4 growth spiral imaged, during precipitation,
with AFM. Bright and dark lines are elementary
step edges, each only 0.75 nm high.
interfaces. The approach to studying these kinetics utilizes in-situ Atomic Force Microscopy (AFM), and hydrodynamic (e.g., channel-flow cell, and wall-jet flow cell) studies of heterogeneous kinetics under well-defined chemical and transport conditions. This research will provide a new level of understanding of the interaction and influence of inorganic as well as organic contaminants on growth and dissolution kinetics of minerals such as alkaline earth sulfates, phosphates, and carbonates and molecular-scale step dynamics and chemistry of solid surfaces.
Adsorption at Solid-Liquid Interfaces: Many problems in aqueous geochemistry, corrosion and scaling inhibition involve adsorptive interaction between organic molecules and solid surfaces. Unfortunately, the AFM is relatively insensitive to composition of the surface under the probe. We are developing new analytical approaches that utilize the specific binding of certain functional groups to various metal sites on solid surfaces to lead to a new AFM-based tool for surface composition mapping. In one such scheme, we use alkane thiols, with a propensity for binding to soft acids, to label heavy metals (soft acids) amidst a background of alkaline earth cations (hard acids) on solid carbonate mineral surfaces.
Instrumentation: The observation of molecular scale reactions with scanning probe microscopy represents one of my key research areas. I have developed a Hydrothermal AFM (HAFM) that operates in highly corrosive fluids and significantly extends the pressure and temperature range of AFM technologies. There are two major reasons why this development is important to materials-related and environmental problems. First, in situ observations are usually required to describe the underlying mechanism in a reaction of interest. Second, the AFM is a valuable structural characterization tool, but has poor detection limits when used to observe dynamics. It is difficult to discuss mechanisms without kinetic experimental data to interrogate. To surmount this shortcoming of the AFM, elevated temperatures assist by accelerating heterogeneous reaction rates. This research will continue to push the limits of temperature and pressure in the AFM that will expand our research base to include studies under supercritical CO2, conditions that are important to testing the feasibility of CO2 sequestration strategies.
PhD and MS Fellowships
Graduate student assistantships are available in the Chemistry Department (MS degree) and the Environmental Science Program (PhD degree) at Wright State University (Dayton, Ohio, USA) in the areas of mineral-fluid interface chemistry. Graduate students will be conducting independent research under the direction of Prof. Steven Higgins on carbonate dissolution and mineralization using scanning probe microscopy, x-ray photoelectron spectroscopy, x-ray scattering and modern analytical chemical instrumentation. Research projects will focus on fundamental and applied problems relevant to geologic CO2 sequestration (goto www.chm.wright.edu/higgins/research.html for more information). Projects involve collaborative efforts with scientists at Department of Energy (DOE) National Laboratories and opportunities to travel and work at DOE facilities will be available to graduate students. Stipends for PhD candidates are $22,660 plus full tuition in 2011 and for MS candidates are about $17,000 plus full tuition. Support for 5 years is available for students pursuing a PhD. Applicants should hold or expect to earn a BS or BA in Chemistry, Earth Science, or Physics prior to starting in either program. To learn more about Wright State University and the Dayton, Ohio area, please visit http://www.wright.edu. To learn more about and/or apply for the PhD program in Environmental Sciences, please go to:
Students interested in pursuing an MS in Chemistry may learn more about the program at:
Interested candidates should contact:
Steven R. Higgins (firstname.lastname@example.org)
Associate Professor of Chemistry
Associate Director - Environmental Science PhD Program
Wright State University
3640 Col. Glenn Hwy.
Dayton, OH 45435
Postdoctoral Search (search closed): Chemistry/Earth Science/Physics
A postdoctoral research associate position in the area of mineral-water interface chemistry and dynamics is available in the Chemistry Department at Wright State University starting on or after May 1, 2009. The position will be for one year, with the potential for extension subject to mutual consent and funding availability. A Ph.D. in Chemistry, Earth Science, Physics, or a closely related discipline is required prior to the date of hire. ABDs and recent graduates are encouraged to apply. Experience in Scanning Probe Microscopy (SPM), or in x-ray scattering methods is highly desired. Experience in computer programming and/or in analytical chemical and instrumental methods of solution analysis is also a plus. The postdoctoral researcher will work effectively under the supervision and mentorship of Prof. Steven R. Higgins and will conduct experimental research on mineral surface chemistry, work with graduate and undergraduate students on research projects, present research results at national and/or international conferences, prepare manuscripts for submission to peer-reviewed journals, and contribute to research proposal preparation. Applicants must submit a cover letter, CV (including list of publications), and names and contact information for three references to our online employment site: https://jobs.wright.edu/applicants/Central?quickFind=50722. Consideration of applications will begin April 1, 2009. AA/EO Employer.