| Abstract: | Uranium adsorption on ferrihydrite was studied as a function of pH in systems equilibrated with air, in the presence and absence of added phosphate and humic acid (HA). The objective was to determine the influence of PO43- and HA on uranium uptake. Below pH 7, the sorption of UO22+ typically increases with increasing pH (the ‘low pH sorption edge‘), with a sharp decrease in sorption above this pH value (the ‘high pH edge‘). The presence of ??PO43- of 10-4 mol/L moved the low pH edge to the left by approximately 0.8 pH units. The PO43- was strongly bound by the ferrihydrite surface, and the increased uptake of U was attributed to the formation of ternary surface complexes involving both UO22+ and PO43-. The addition of HA (9 mg/L) increased U uptake at pH values below 7, with little effect at higher pH values. The positions of the pH edges were also affected by the ionic strength and total U content. These experiments show that sorption interactions involving PO43 and HA must be considered in order to model the behavior of U in natural systems, in which these components are often present. |
| Genre: | Article |
| ProdID: | 70018168 |
| Citation Author: | Payne, T. E.; Davis, J. A.; Waite, T. D. |
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| Citation End Page: | 243 |
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| Citation Language: | English |
| Citation Larger Work Title: | Radiochimica Acta |
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| Citation Number Of Pages: | 5 |
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| Citation Search Results Text: | Uranium Adsorption on Ferrihydrite - Effects of Phosphate and Humic Acid; 1996; Article; Journal; Radiochimica Acta; Payne, T. E.; Davis, J. A.; Waite, T. D. |
| Citation Start Page: | 239 |
| Citation Volume: | 74 |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | Uranium Adsorption on Ferrihydrite - Effects of Phosphate and Humic Acid; 1996; Article; Journal; Radiochimica Acta; Payne, T. E.; Davis, J. A.; Waite, T. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1996 00:00 -0600 |
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