Implications of recently derived thermodynamic data and specific ionic interaction theory parameters for (Mg/Ca)UO(CO) complexes on the predominance of the Mg-Ca-UO-OH-CO systems, and application to natural and legacy-mine waters.

The formation of alkaline earth(II)triscarbonatouranyl(VI) (AeUO(CO)) species that have been evidenced both in laboratory and in-field studies, is important from slightly acidic pH up to near degraded cementitious in carbonated waters. They are also showing distinctive luminescence properties with a hypsochromic shift relative to UO. The conditions of pH, activities of alkaline earth(II) free ions (mostly Mg and Ca) and carbonate ions (HCO) can be predicted from the thermodynamic functions and constants.

Measurement and modeling of the surface potential evolution of hydrated cement pastes as a function of degradation.

Hydrated cement pastes (HCP) have a high affinity with a lot of (radio)toxic products and can be used as waste confining materials. In cementitious media, elements are removed from solution via (co)precipitation reactions or via sorption/diffusion mechanisms as surface complexation equilibria. In this study, to improve the knowledge of the surface charge evolution vs the degradation of the HCP particles, two cements have been studied: CEM-I (ordinary Portland cement, OPC) and CEM-V (blast furnace slag and fly ash added to OPC).

Mechanism of europium retention by calcium silicate hydrates: an EXAFS study.

The uptake of Eu by calcium silicate hydrate (C-S-H) phases as a function of Eu/sorbate ratio (from 37 to 450 micromol g(-1) C-S-H), C-S-H Ca/Si mole ratio (1.3, 1.0, and 0.