A luminescence line-narrowing spectroscopic study of the uranium(vi) interaction with cementitious materials and titanium dioxide. Issue 3 (18th November 2014)

• Record Type: Journal Article
• Authors: Tits, Jan; Walther, Clemens; Stumpf, Thorsten; Macé, Nathalie; Wieland, Erich
• Is Part Of: Dalton transactions. Volume 44:Issue 3(2015)
• Page Start: 966
• Page End: 976
• Publication Date: 2014-11-18
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c4dt02172j
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Luminescence line-narrowing spectroscopy has been applied to identify the mechanisms controlling the uranium retention by titanium dioxide and cement minerals. Abstract : Non-selective luminescence spectroscopy and luminescence line-narrowing spectroscopy were used to study the retention of UO2 2+ on titanium dioxide (TiO2 ), synthetic calcium silicate hydrate (C-S-H) phases and hardened cement paste (HCP). Non-selective luminescence spectra showed strong inhomogeneous line broadening resulting from a strongly disordered UO2 2+ bonding environment. This problem was largely overcome by using luminescence line-narrowing spectroscopy. This technique allowed unambiguous identification of three different types of UO2 2+ sorbed species on C-S-H phases and HCP. Comparison with spectra of UO2 2+ sorbed onto TiO2 further allowed these species to be assigned to a surface complex, an incorporated species and an uranate-like surface precipitate. This information provides the basis for mechanistic models describing the UO2 2+ sorption onto C-S-H phases and HCP and the assessment of the mobility of this radionuclide in a deep geological repository for low and intermediate level radioactive waste (L/ILW) as this kind of waste is often solidified with cement prior to storage.