22541-40-8Relevant academic research and scientific papers
Adsorption and recovery of U(vi) from low concentration uranium solution by amidoxime modified Aspergillus niger
Li, Le,Hu, Nan,Ding, Dexin,Xin, Xin,Wang, Yongdong,Xue, Jinhua,Zhang, Hui,Tan, Yan
, p. 65827 - 65839 (2015/08/18)
Amidoxime modified Aspergillus niger (AMAN) was prepared by the oximation reaction. The effects of the initial pH, contact time, initial U(vi) concentration and biosorbent dose on the adsorption of U(vi) ions from radioactive wastewater in U(vi) concentrations of less than 1 mg L-1 by AMAN and the raw Aspergillus niger (RAN) were investigated. The maximum adsorption efficiency by AMAN for the 0.5 mg L-1 U(vi) solution amounted to 98.85% under the optimum adsorption conditions, while the maximum adsorption efficiency by RAN was only 77.83%. The adsorption equilibrium data were found to be best fitted to Langmuir isotherm model, and the maximum biosorption capacity of AMAN for U(vi) was estimated to be 621 mg g-1 at 298 K. The biosorption kinetics followed the pseudo-second order model and intraparticle diffusion equation. The Gibbs free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) showed that the adsorption process of U(vi) was spontaneous, feasible and endothermic. The SEM-EDS study indicated that much more U(vi) ions were adsorbed by AMAN than by RAN. FT-IR study showed that the -NH2 and =N-OH groups of amidoxime were the dominant ones for binding UO22+ ions. Moreover, AMAN was found to have excellent selective adsorption capability of U(vi) due to amidoxime groups. The UO22+ ions adsorbed by AMAN could be desorbed using 0.1 M HCl, and the desorption efficiency reaching 87.28% at the 8th cycle of adsorption and desorption.
Radiolytic yield of UIV oxidation into UV1: A new mechanism for Uv reactivity in acidic solution
Atinault,De Waele,Belloni,Le Naour,Fattahi,Mostafavi
, p. 2080 - 2085 (2010/07/05)
The yields of the radiolytic oxidation of UIV and of the U VI formation, measured by spectrophotometry, are found to be the same (G(-UIV)N2o - G(UVI)N20 = 8.4 x 10 -7 mol J-1) and almost double the H2 formation yield (G(H2) = 4.4 x 10-7 mol J-1) in the 60Co y radiolysis of N2O-aqueous solutions in the presence of 2 mol L-1 Cl- at pH - 0 (HCl). According to the mechanism of UIV radiolytic oxidation, we show that under the conditions of our experiments the Uv ions do not disproportionate, but undergo a stoichiometric oxidation into UVI by H- with forming H2.
CHEMISTRY OF URANIUM IN GLASS-FORMING MELTS: REDOX INTERACTIONS OF URANIUM WITH CHROMIUM AND IRON IN ALUMINOSILICATES.
Schreiber,Balazs,Kozak
, p. 340 - 346 (2008/10/08)
The objectives of this study were to determine the degree and the nature of the mutual interactions of uranium with chromium and with iron by internal redox reactions within aluminosilicate melts.
Electronic spectral studies of some uranium(V) compounds
Selbin,Ortego,Gritzner
, p. 976 - 982 (2008/10/08)
The following solid compounds were prepared and characterized in inert atmospheres: MUCl6 (M = Rb and (n-C3H7)4N), both new compounds in regard to the cation present; UCl5·SOCl2; UCl5·PCl5; and UCl5·TCAC (TCAC = trichloroacrylyl chloride, Cl2C=CClCOCl), a new compound. In addition, solutions of UCl5 in CCl4 and SiCl4 were prepared. Infrared spectra were obtained. Electronic spectra in the near-ir and visible region were obtained for the MUCl6 compounds dissolved in SOCl2; for UCl5·TCAC dissolved in SOCl2, C6H6, CS2, and CCl4; for UCl5·SOCl2 dissolved in SOCl2 and CCl4; and for UCl5 in CCl4 and SiCl4. Electronic as well as vibronic band assignments have been made for these 5f1 electronic systems and several of the vibrational frequencies of the UCl6- species have been deduced from the electronic spectra. The first esr spectra for pure U(V) compounds, obtained with powdered samples, are reported, and the average g values are all 1.1.
