Time-resolved analytical methods for liquid/solid interfaces. Progress report, March 1, 1993--November 15, 1993
Chemical phenomena occurring at boundaries between insulating solids and liquids (adsorption, partition, monolayer self-assembly, catalysis, and chemical reactions) are important to energy-related analytical chemistry. These phenomena are central to chromatography, solid-phase extraction, immobilized analytical reagents, and optical sensors. Chemical interactions in these processes cannot generally be identified solely by equilibrium surface concentrations, since the steady-state behavior does not reveal the mechanism or rates of surface reactions. Goal therefore is to develop surface-sensitive spectroscopies by which chemical kinetics at liquid/solid interfaces can be observed on time-scales from nanoseconds to seconds. In the first year, we have used Joule-discharge heating kinetics to study pore structure of silica gels; effects of pore diameter, particle size, and chemical modification on pore connectivity were investigated. Temperature-jump relaxation measurements of sorption/desorption kinetics at liquid/solid interfaces were also carried out using Joule heating; kinetic barriers to sorption of ions from solution were found for both C18 and Cl surfaces. Through a collaboration with Fritz-Haber Institute in Berlin, we were able to acquire laser temperature-jump data on kinetics at liquid/solid interfaces using a colloidal sample. We also quantified the rate of migration of covalently attached ligands on silica surfaces; from the temperature dependence, the large energy barrier to migration was estimated. A review of applications of electronic spectroscopy (absorption and fluorescence) to reversed-phase chromatographic interfaces was published.
- Research Organization:
- Utah Univ., Salt Lake City, UT (United States). Dept. of Chemistry
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG03-93ER14333
- OSTI ID:
- 10134247
- Report Number(s):
- DOE/ER/14333-1; ON: DE94008352; BR: KC0302020
- Resource Relation:
- Other Information: PBD: 15 Nov 1993
- Country of Publication:
- United States
- Language:
- English
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