Batch experiments with Eu, Sr and Cs

The experimental set-up for batch-experiments as described here is applied for the long-term safety relevant elements Eu, Sr, and Cs in combination with muscovite, quartz, and orthoclase. To collect this data two diploma theses were assigned (Britz (2011), Fricke (2014)). Detailed information can be obtained from Noseck et al. (2012) and Britz (20018).

Two solid/liquid ratios (M/V) are used and four element concentrations ranging between 10-5 - 10-8 mol L-1; pH-values range between 3 and 9. Experiments are carried out threefold for subsequent statistical evaluation.

  • Minerals: muscovite, orthoclase, quartz
  • Elements: Eu3+, Cs+, Sr2+
  • Element concentration: 10-5, 10-6, 10-7, 10-8 mol L-1
  • Solid-liquid ratio: 1/20 and 1/80 g ml-1
  • pH: 3 - 9
  • Background electrolyte: 0.01 mol L-1 NaClO4

 

Results mainly follow expectations for all batch experiments. Exemplarily, measurements of Eu3+ sorption experiments on quartz (grey), orthoclase (blue) and muscovite (green) are illustrated in Fig. 1. Generally, a strong pH dependency can be observed for all minerals with nicely represented sorption edges. The influence of different M/V ratios is also obvious: The higher the amount of mineral phase, the more Eu sorbes to the surface. Furthermore, typical mineralogical traits can be observed; such as for muscovite: Cation exchange processes result in minimum %Eu(III) immobilized values of approximately 20% for the phyllosilicate. For more detailed information please see Britz (20018).

 

Fig. 1: Results of Eu batch experiments with orthoclase (blue), quartz (grey), and muscovite (green) (10 mM NaClO4 background electrolyte, laboratory conditions: CO2 10−3.4 bar, T = 296.0 K ± 2 K). C0 – initial Eu concentration.

PHREEQC (Parkhurst and Appelo, 1999) in combination with UCODE (Poeter et al., 2005) is used to determine surface complexation parameters via inverse modeling. Results are discussed in detail in Noseck et al. (2012) and Britz (20018).

 

 

 

References:

Noseck, U., Brendler, V., Flügge, J., Stockmann, M., Britz, S., Lampe, M., Schikora, J., Schneider, A. (2012). Realistic integration of sorption processes in transport codes for long-term savety assessments. GRS-297, BMWi-FKZ 02E10518, Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH, Braunschweig, 293 p.

Parkhurst, D.L. & Appelo, C.A.J., (1999). User’s guide to PHREEQC (Version 2) - A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations, U.S. Geological Survey Water-Resources Investigations Report 99-4259, 312 p.

Poeter, E.P., Hill, M.C., Banta E.R., Mehl, S., Christensen, S. (2005). UCODE_2005 and Six Other Computer Codes for Universal Sensitivity Analysis, Calibration, and Uncertainty Evaluation, U.S Geological Survey, Techniques and Methods 6-A11, 299 p.

Britz, S.: Europium sorption experiments with muscovite, orthoclase, and quartz: Modeling of surface complexation and reactive transport, PhD thesis, DOI 10.24355/dbbs.084-201806051207-0, GRS Braunschweig, Theodor-Heuss-Sr. 4, Abt. 401, 38122 Braunschweig (2018).

Fricke, J.: Sorption of Europium on Quartz – Batch experiments and geochemical modelling, Master thesis, available at: GRS Braunschweig, Theodor-Heuss-Sr. 4, Abt. 401, 38122 Braunschweig (2014).

 

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