Modeling and experimental validation of colloid facilitated cesium transport in porous media /
Groundwater colloids can act as a vector which enhances the
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739363601&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Groundwater colloids can act as a vector which enhances the migration of contaminants. In this study, an idealized laboratory set-up was used to examine the influence of amorphous silica colloids on the transport of cesium. Synthetic groundwater and -saturated glass bead columns were used to minimize the presence of natural colloidal material. The columns were assembled in replicate, some packed with 150-210 um glass beads and others packed with 355-420 Jim glass beads. The colloids used in these experiments were 100 nm amorphous silica colloids from Nissan Chemical Company. In independent batch sorption experiments, non-linear Freundlich isotherms were found to best describe the sorption of cesium to both silica colloids and glass beads. In the absence of colloids, the retardation factor for cesium was 8.0 in the 150-210 um glass bead columns and 3.6 in the 355- 420 um glass bead columns. The influence of anthropogenic colloids was tested by injecting 0.09 pore volume slug of an equilibrated suspension of cesium and colloids into the colloid-free columns. Although there was little noticeable facilitation in the smaller glass bead columns, there was a slight reduction in the retardation of cesium in the larger glass bead columns. This was attributed to cesium having less of a retention time in the larger glass bead columns. When cesium was injected into columns with a constant flux of colloids, the retardation of cesium was reduced by 14-32% in the 150-210 um glass bead columns and by 38-51% in the 355- 420 um glass bead columns. Models based on Coi-apcioglu and Jiang [1993] were compared with the experimental elution data. When equilibrium sorption expressions were used and the flux of colloids through the glass bead columns was constant , the colloid facilitated transport of cesium was able to be described using an effective retardation coefficient. Fully kinetic simulations) however, more accurately described the colloid facilitated transport of cesium. |
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| Item Description: | Vita. "Major Subject: Civil Engineering". |
| Physical Description: | xviii, 149 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 126-129. |