This dissertation presents the results of laboratory experiments in which essential aspects of the movement of F- in saturated media have been addressed. The interactions between F-solutions and quartz, vermiculite, and kaolinite were studied through batch and column experiments. Quartz was found to react slightly with F⁻ , giving data described by a quasi-linear isotherm. Vermiculite adsorbed only minute amounts of F. A large uptake of F⁻ by kaolinite was measured. Ion exchange F⁻ by 0H⁻. may not have been the exclusive mechanism operating under the experimental conditions. The kinetics of the dissolution of fluorite (CaF₂) were investigated by means of batch and column tests. There appears to be a relationship between the dissolution rate and the mean flow velocity. Solution pHs greater than 5-6 may accelerate the dissolution process. For temperatures between 15 and 30°C, the dissolution is characterized by an activation energy of about 7 Kcal/mole, which would indicate that both surface reaction and transport are the rate-limiting step. The percolation of columns containing quartz, vermiculite, and kaolinite with multi-component solutions (including F⁻) resulted in a late breakthrough of F⁻ when compared with that of the other species. Circulation of distilled water led to an almost complete recovery of the F⁻ injected, which exited the column with relative concentrations greater than 1. When the packing included fluorite and distilled water was flushed through the column for 2 days, a concentration of F⁻ of about 1.3 pprn was rapidly reached and remained constant throughout the run. Multivariate analysis techniques (factor and correspondence analyses) were applied to data from two aquifers known to carry high F-waters. Although helpful in discriminating major and minor associations of species, none of those techniques could help unravel the behavior of F⁻ in the study aquifers. It is suggested that laboratory and field studies be continued and that, for the successful modeling of the movement and distribution of F⁻ in aquifers, non-linear source/sink terms should be included in the pertinent differential equation governing the transport of solutes.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/191137 |
| Date | January 1988 |
| Creators | Usunoff, Eduardo Jorge. |
| Contributors | Davis, Stanley N., Ruiz, Joaquin, Long, Austin, Sorooshian, Soroosh, Simpson, Eugene S. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Dissertation-Reproduction (electronic), text |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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