title: Sorption Mechanisms of Eu(3+) on CSH Phases of Hydrated Cements.
abstract: The sorption mechanisms of Eu(3+) on calcium silicate hydrate (CSH) phases of hydrated cement were investigated as a tool for the prediction of the behavior of trivalent radionuclides with aged/degraded cements in radioactive waste repositories. Four techniques were used: site-selective and time-resolved luminescence spectroscopy, XPS, high-resolution SEM coupled with EDX, and XRD. Results showed that europium is not precipitated in the solution despite its low solubility limit. It is strongly retained on CSH, resulting in a more than 99.8% sorption rate. Two main sorption sites were characterized by luminescence spectroscopy. One site, with a long lifetime, can be interpreted as Eu included in the framework of CSH. Another one, with a shorter lifetime, can be interpreted as a site with a hydrated environment that is high but is less than that of europium hydroxide. It corresponds to superficial complexation or precipitation. Copyright 2001 Academic Press.
authors.affiliation: Groupement de Recherche en Chimie Inorganique, Université de Reims, REIMS Cedex, 51687, France
authors.forename: Ingmar
authors.initials: I
authors.lastname: Pointeau
authors.forename: Bernard
authors.initials: B
authors.lastname: Piriou
authors.forename: Michel
authors.initials: M
authors.lastname: Fedoroff
authors.forename: Marie-Genevieve
authors.initials: MG
authors.lastname: Barthes
authors.forename: Nicolas
authors.initials: N
authors.lastname: Marmier
authors.forename: Francine
authors.initials: F
authors.lastname: Fromage