In numerous reports on selective solid-phase extraction (SPE) of uranium, the extraction of uranium is generally accepted as a direct coordination of the ligands on the solid matrix with the uranyl, in which the critical effect of the hydration shell on the uranyl is neglected. The related mechanism in the extraction process remains unclear. Herein, the detailed calculation of activation energy...

The structure of uranopilite, [(UO2)6(SO4)O2(OH)6(H2O)6](H2O)8, space group P1̄, a 8.896(2), b 14.029(3), c 14.339(3) Å, 96.610(4), 98.472(4), 99.802(4)°, V 1726.1(4) Å3, Z = 2, has been solved and refined on the basis of F2 for all unique data collected with monochromatic MoK X-radiation and a CCD-based detector to an agreement factor (R1) of 7.0%, calculated using 3907 unique observed reflecti...

The speciation of uranyl ions in fulvic acid (FA) and humic acid (HA), based on models of larger sizes, is systematically studied using density functional theory (DFT). Four uranyl binding sites are suggested for FA and based on their energetics, the preferential binding sites are proposed. The computed binding sites include two chelating types, one through the carboxylate group and one via the...

To better understand the association of contaminant uranium with natural organic matter (NOM) and the fate of uranium in ground water, spectroscopic studies of uranium complexation with catechol were conducted. Catechol provides a model for ubiquitous functional groups present in NOM. Liquid samples were analyzed using Raman, FTIR, and UV-Vis spectroscopy. Catechol was found to polymerize in pr...

The effects on postnatal development and behavior were assessed in the offspring of female rats concurrently exposed to uranium (U) and restraint stress. Adult female rats were administered uranyl acetate dihydrate (UAD) in the drinking water at doses of 0, 40 and 80 mg/(kg day) for 4 weeks before mating with untreated males, as well as during pregnancy and lactation. One-half of female rats in...

Sulfate-rich acid waters produced by oxidation of sulfide minerals enhance U mobility around U ores and U-bearing radioactive waste. Upon evaporation, several secondary uranyl minerals, including many uranyl sulfates, precipitate from these waters. The zippeite-group of minerals is one of the most common and diverse in such settings. To decipher the nature and crystal chemistry of the zippeite-...

The structure of haiweeite, Ca[(UO2)2Si5O12(OH)2](H2O)3, Z = 4, orthorhombic, a 7.125(1), b 17.937(2), c 18.342(2) Å, V 2344.3(7) Å3, space group Cmcm, has been solved by direct methods and refined by full-matrix least-squares techniques to an agreement index (R1) of 4.2% for 1181 unique observed reflections (|Fo| ≤ 4 F) collected using MoK X-radiation and a CCDbased area detector. The structur...