| Abstract: | The transport of adsorbing and complexing metal ions in porous media was investigated with a series of batch and column experiments and with reactive solute transport modeling. Pulses of solutions containing U(VI) were pumped through columns filled with quartz grains, and the breakthrough of U(VI) was studied as a function of variable solution composition (pH, total U(VI) concentration, total fluoride concentration, and pH-buffering capacity). Decreasing p H and the formation of nonadsorbing aqueous complexes with fluoride increased U(VI) mobility. A transport simulation with surface complexation model (SCM) parameters estimated from batch experiments was able to predict U(VI) retardation in the column experiments within 30%. SCM parameters were also estimated directly from transport data, using the results of three column experiments collected at different pH and U(VI) pulse concentrations. SCM formulations of varying complexity (multiple surface types and reaction stoichiometries) were tested to examine the trade-off between model simplicity and goodness of fit to breakthrough. A two-site model (weak- and strong-binding sites) with three surface complexation reactions fit these transport data well. With this reaction set the model was able to predict (1) the effects of fluoride complexation on U(VI) retardation at two different pH values and (2) the effects of temporal variability of pH on U(VI) transport caused by low p H buffering. The results illustrate the utility of the SCM approach in modeling the transport of adsorbing inorganic solutes under variable chemical conditions. |
| Genre: | Article |
| ProdID: | 70018600 |
| Citation Author: | Kohler, M.; Curtis, G. P.; Kent, D. B.; Davis, J. A. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 3551 |
| Citation Issue: | 12 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Water Resources Research |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 13 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Experimental investigation and modeling of uranium (VI) transport under variable chemical conditions; 1996; Article; Journal; Water Resources Research; Kohler, M.; Curtis, G. P.; Kent, D. B.; Davis, J. A. |
| Citation Start Page: | 3539 |
| Citation Volume: | 32 |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | Experimental investigation and modeling of uranium (VI) transport under variable chemical conditions; 1996; Article; Journal; Water Resources Research; Kohler, M.; Curtis, G. P.; Kent, D. B.; Davis, J. A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1996 00:00 -0600 |
| Publisher: | |
