%0 Journal Article
%A Lange, Steve
%A Klinkenberg, Martina
%A Barthel, Juri
%A Bosbach, Dirk
%A Deissmann, Guido
%T Uptake and retention of molybdenum in cementitious systems
%J Applied geochemistry
%V 119
%@ 0883-2927
%C Amsterdam [u.a.]
%I Elsevier Science
%M FZJ-2020-02198
%P 104630
%D 2020
%X The uptake of molybdenum, present in aqueous cementitious environments in the form of the molybdate ion (MoO42-), by various cement hydration phases such as calcium-silicate-hydrates (C–S–H), monosulphate (AFm), ettringite (AFt), as well as hardened cement paste made from Ordinary Portland cement (OPC), was studied in batch-type sorption experiments under anoxic conditions. Uptake kinetics were generally fast, leading to sorption equilibrium in less than 30 days. In particular, a strong uptake of molybdate by AFm phases was observed as well as a distinct contribution of C–S–H phases to the molybdate retention in cementitious systems, the latter depending on the Ca/Si-ratio of the C–S–H and the alkali content in solution. In systems containing hydrogarnet, the neo-formation of a molybdate-bearing AFm phase was identified as an additional process contributing to molybdate retention. The findings have implications for selecting grouts for the immobilisation of radioactive waste streams containing Mo-93 and also enhance the data available on molybdate sorption and retention in cementitious systems.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000556136100008
%R 10.1016/j.apgeochem.2020.104630
%U https://juser.fz-juelich.de/record/877445