caa a22 4500 378927027 CHVBK 20180305123620.0 cr unu---uuuuu 161128e20041101xx s 000 0 eng 10.1524/ract.92.9.645.55008 doi (NATIONALLICENCE)gruyter-10.1524/ract.92.9.645.55008 Reproducibility of the uptake of U(VI) onto degraded cement pastes and calcium silicate hydrate phases [Elektronische Daten] [I. Pointeau, Catherine Landesman, E. Giffaut, Pascal Reiller] The U(VI) uptake in degraded cement pastes was undertaken in the laboratories of CEA/L3MR and SUBATECH in order to check the reproducibility of the study. Two well hydrated cement pastes, CEM I (Ordinary Portland Cement, OPC) and CEM V (blast furnace slag (BFS) and fly ash added to OPC) were degraded using similar protocols. Equilibrium solutions and solid materials were characterised for three degradation states for each paste. All samples are free of portlandite and the pH of the equilibrated cement solutions vary in the range 9.8-12.2. Three calcium silicate hydrate phases (C-S-H) were synthesised in order to compare the sorption properties of degraded cement pastes and of hydrate phases in similar pH conditions. In order to avoid precipitation processes, the operational solubility limit was evaluated before batch experiments. These solubility values vary significantly in the pH range [9-13] with a 2.4×10-7mol L-1 minimum at pH close to 10.5. In batch sorption experiments, the distribution ratio Rd values are high: 3×104-1.5×105mL g-1. The uptake of U(VI) increases when comparing the least and the most degraded cement pastes whereas the initial composition of cement has relatively insensitive effect. Sorption isotherms, expressed as a log[U(VI)solid]/log [U(VI)solution] plots are linear. A slope of 1 is calculated indicating the predominance of sorption processes. As sorption and desorption values are close, the uptake mechanism seems reversible. The Rd values measured in C-S-H suspensions are in good agreement with Rd values of degraded cement pastes, and C-S-H materials could be one of the cementitious phases which control U(VI) uptake in cement pastes. © 2004 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Pointeau I. aut Landesman Catherine aut Giffaut E. aut Reiller Pascal aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/9-11/2004(2004-11-01), 645-650 0033-8230 92:9-11/2004<645 2004 92 ract https://doi.org/10.1524/ract.92.9.645.55008 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.92.9.645.55008 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pointeau I. aut NATIONALLICENCE 700 1- Landesman Catherine aut NATIONALLICENCE 700 1- Giffaut E. aut NATIONALLICENCE 700 1- Reiller Pascal aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/9-11/2004(2004-11-01), 645-650 0033-8230 92:9-11/2004<645 2004 92 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter