Grantee Research Project Results
1999 Progress Report: Analysis of Halogenated Organic Particle-Scale Desorption via Column Studies and 13C Solid State NMR Spectroscopy
EPA Grant Number: R822626Title: Analysis of Halogenated Organic Particle-Scale Desorption via Column Studies and 13C Solid State NMR Spectroscopy
Investigators: Reinhard, Martin
Institution: Stanford University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1995 through August 1, 1998 (Extended to August 31, 2000)
Project Period Covered by this Report: September 1, 1998 through August 1, 1999
Project Amount: $177,916
RFA: Exploratory Research - Chemistry and Physics of Water (1995) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Safer Chemicals
Objective:
The objective of this project is to elucidate the mechanisms controlling the slow desorption of volatile organic chemicals from soils and sediments using column studies and 13C solid state nuclear magnetic resonance (NMR) spectroscopy. Column studies involve measuring desorption isotherm and kinetic profiles for trichloroethylene (TCE) on model and natural solids over a 45 C temperature range. NMR spectroscopy will be used to compare the resonance frequency of TCE, sorbed to model and natural solids, to the resonance frequency of pure phase and aqueous phase TCE. These studies will allow contaminant transport models to be developed that consider slow desorption and the effects of temperature on this process. These studies also will allow decision makers to gauge the viability of enhanced thermal recovery methods with respect to slow desorption.Progress Summary:
The focus during 1999 was on the competitive desorption of TCE and tetrachloroethylene (PCE) from humidity from silica gel and two well characterized natural solids. Binary solute desorption isotherms at 100 percent relative humidity from silica gel, Norwood soil, and Santa Clara aquifer material?materials used previously. Results indicated that the ideal adsorbed solution theory (IAST) was able to describe desorption isotherms for the silica gel. For the natural solids, IAST was not able to describe desorption isotherms for the full concentration range examined. Failure of IAST was greatest for the most heterogeneous sorbent, even when considering multiple sorption domains. In addition, IAST predictions worsened as nonlinear uptake mechanisms began to dominate. Several possible explanations for the failure of the IAST are given, including the possibility that complex interactions between the sorbing solutes and the sorbent may exist, causing deviations from ideal sorption behavior.Future Activities:
During the current and final year, the kinetics of competitive desorption will be evaluated using data collected during the first 3 years and the desorption model developed as part of this project.Journal Articles on this Report : 6 Displayed | Download in RIS Format
| Other project views: | All 11 publications | 7 publications in selected types | All 7 journal articles |
|---|
| Type | Citation | ||
|---|---|---|---|
|
|
Cunningham JA, Werth CJ, Reinhard M, Roberts PV. Effects of grain-scale mass transfer on the transport of volatile organics through sediments. 1. Model development. Water Resources Research 1997;33(12):2713-2726. |
R822626 (1999) R822626 (Final) |
not available |
|
|
Schaefer CE, Schuth C, Werth CR, Reinhard M. Binary desorption isotherms of TCE and PCE from silica gel and natural solids. Environmental Science & Technology 2000;34(20):4341-4347. |
R822626 (1999) R822626 (Final) |
not available |
|
|
Werth CJ, Cunningham JA, Roberts PV, Reinhard M. Effects of grain-scale mass transfer on the transport of volatile organics through sediments 2: Column results. Water Resources Research 1997;33(12):2727-2740. |
R822626 (1999) R822626 (Final) |
not available |
|
|
Werth CJ, Reinhard M. Effects of temperature on trichloroethylene desorption from silica gel and natural sediments. 1. Isotherms. Environmental Science & Technology 1997;31(3):689-696. |
R822626 (1999) R822626 (Final) |
not available |
|
|
Werth CJ, Reinhard M. Effects of temperature on trichloroethylene desorption from silica gel and natural sediments. 2. Kinetics. Environmental Science & Technology 1997;31(3):697-703. |
R822626 (1999) R822626 (Final) |
not available |
|
|
Werth CJ, Reinhard M. Counter diffusion of isotopically labeled trichloroethylene in silica gel and geosorbent micropores: Column results. Environmental Science & Technology 1999;33(5):730-736. |
R822626 (1999) R822626 (Final) |
not available |
Supplemental Keywords:
competitive desorption, modeling, TCE, PCE, VOCs, remediation., Scientific Discipline, Toxics, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Contaminated Sediments, Environmental Chemistry, Physics, HAPS, Chemistry, Fate & Transport, Engineering, Chemistry, & Physics, fate and transport, mass spectrometry, zeolites, contaminated sediment, spectroscopic studies, VOCs, particle scale desorption, Trichloroethylene, chemical composition, chemical detection techniques, mass transfer, spectroscopy, chemical kinetics, column studiesProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.