Sorption of uranium(6+) and neptunium(5+) by surfactant-modified natural zeolites
Experiments were conducted to determine the ability of surfactant-modification to enhance the ability of natural zeolites to sorb U(6+) and Np(5+). Natural zeolite material, comprised mainly of clinoptilolite and treated with the cationic surfactant hexadecyltrimethylammonium-bromide (HDTMA), was reacted with U(6+) and Np(5+) solutions open to the atmosphere and having a range of radionuclide concentration, pH, and NaCl concentration. The results indicate surfactant-modification of the zeolite enhances its ability to sorb U(6+), particularly at pHs greater than six where U(6+) sorption on unmodified zeolite is typically low due to formation of anionic U(6+) aqueous carbonate complexes. In contrast, there is little enhancement of Np(5+) sorption onto surfactant-modified zeolite. The presence of chloride anions in solution makes surfactant-modification less effective. The enhanced sorption of U(6+) is interpreted to be due to anion exchange with counterions on the external portion of a surfactant bilayer or admicelles.
- Research Organization:
- Southwest Research Inst., San Antonio, TX (US)
- OSTI ID:
- 20015861
- Resource Relation:
- Conference: 1998 Materials Research Society Fall Meeting, Boston, MA (US), 11/30/1998--12/04/1998; Other Information: Single article reprints are available from University Microfilms Inc., 300 North Zeeb Road, Ann Arbor, Michigan 48106; PBD: 1999; Related Information: In: Scientific basis for nuclear waste management XXII. Materials Research Society symposium proceedings: Volume 556, by Wronkiewicz, D.J.; Lee, J.H. [eds.], 1355 pages.
- Country of Publication:
- United States
- Language:
- English
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