Sorption of Trace Constituents from Aqueous Solutions Onto Secondary Minerals. I. Uranium

Abstract

Abstract--Well-characterized American Petroleum Institute clay standards, source clays from The Clay Minerals Society, and other secondary minerals were used to determine the effects of U concentration, temperature, and solution composition on U-sorption properties. Uranium concentrations ranged from about 1.00 x 10 -4 M to 4.00 x 10 7 M, temperatures from 5 ~ to 65~ and solution compositions containing 0.01 M NaCl and 0.01 M NaHCO3. Silica gel efficiently sorbed uranyl carbonate anion complexes. The higher cation-exchange capacity materials most readily sorbed uranyl ions from the 0.01 M NaCl solution. Temperature increases tended to affect uranyl ion sorption adversely except when the U was present as carbonate complexes. Noncrystalline ferric oxyhydroxides sorbed uranyl ions much more efficiently than any of the secondary crystalline minerals studied. A method for accurately extrapolating U-sorption efficiencies between experimental points based on the Freundlich equation is presented.

Unsaturated Zone and Saturated Zone Transport Properties (U0100)

“…Montmorillonite was found to have a greater selectivity for the uranyl ion than for sodium and potassium ions in the same solutions. Ames et al (1983) found that uranium was strongly sorbed to montmorillonite fiom 0.01 M NaCl solutions but weakly sorbed from 0.01 M NaHC03 solutions in the pH range from 8 to 9.…”

“…Ames et al (1983) report that clinoptilolite has a low affinity for trace levels of uranium in the plH range from 8 to 9 in 0.01 M NaHC03. Doi et al (1975) found that uranium at concentrations of lo4 g per g of 0 ANL-NBS-HS-000019, Rev 00, ICN 1 solution was strongly sorbed onto clinoptilolite from perchlorate solutions in the pH range from 4 to 8.5.…”

“…Among the solid phases investigated are goethite (for example, Hsi and Langmuir 1985), hematite (Ho and Miller 1986), silica gel (Zielinski 1980), clays (Tsunashima et al 1981), and zeolites (Ames et al 1983). The results reported are sometimes difficult to reconcile.…”

Potential aquifer vulnerability in regions down-gradient from uranium in situ recovery (ISR) sites

“…Sorption of uranium and associated metals and metalloids on mineral surfaces in groundwater systems has been proposed to be an important process in uranium roll-front formation (e.g., Nash et al, 1981;Cuney, 2010). Uranium and associated metals and metalloids (As, Se, V, Mo) in the roll-front ores all apparently have the capability of being sorbed by four common classes of highsurface-area minerals in the roll-front systems: (a) clays (Ames et al, 1983;Wang et al, 2011); (b) iron oxyhydroxides (Dzombak and Morel, 1990); (c) manganese oxyhydroxides (Tani et al, 2004;Wang et al, 2012;and Mukherjee et al, 2013), and (d) Fig. 3.…”

Radioactivity: A Tool to Explore the Past

“…Typical attachment rates for outdoor conditions (aerosol particle concentration (2-7) · 10 4 cm 3 ) were found to be 20-100 h"' [26], corresponding to average attachment times of 40 s to 3 min. For an aerosol particle concentration of only 100 cm" 3 , an attachment time of about 1 hour was observed [27], Of special relevance is the fact, that due to a 112 keV nuclear recoil, the first progeny of the α-emitting nuclide 218 Po, the daughter nuclide 214 Pb, escapes with about 80% probability [28,29] from the particles which have typical median aerodynamic diameters of 50 to 200 nm [28]. In addition, for indoor condition or outdoor situations close to ground, prior to an attachment of the short-lived 222 Rn progenies to aerosol particles, these nuclides may plate-out to nearby-surfaces.…”