Considered systems

Thermodynamic data of aqueous species and mineral phases are derived from referenced and internationally acknowledged data bases (Thermodynamic data). However, a large gap exists regarding sorption data. Hence, experimental studies are undertaken to fill in missing data such as Kd values, surface site areas, surface site densities, protolyses and complexation constants.

Therefore, orthoclase, muscovite and quartz are chosen as major representatives of ubiquitously present minerals in Northern Germany to develop and perform laboratory studies. Even though these minerals are commonly present in porous media sufficient sorption data is missing. Conducted experiments comprise a wide range of defined geochemical conditions and cover extensive laboratory analyses.

Titration experiments:

  • Minerals: muscovite, orthoclase, quartz
  • pH: 3 - 8
  • Background electrolyte: NaClO4

 

Batch experiments:

  • Minerals: muscovite, orthoclase, quartz, synthetic sediment (10% muscovite, orthoclase resp., 80% quartz), natural Gorleben sediment
  • Elements: Eu3+, Cs+, Sr2+, Ni2+, Al3+, UO22+, Np5+, Nd3+
  • Element concentration: 10-5 - 10-8 mol L-1
  • Ligands: CO32-, SO42-
  • Competing cations: Ca2+, Al3+
  • Solid-to-liquid ratio: 1/20 ,1/80, 1/320 g ml-1
  • pH: 3 - 9
  • Background electrolyte: NaClO4, Na2SO4

 

Column experiments:

  • Minerals: muscovite, orthoclase, synthetic sediment (10% muscovite, orthoclase resp., 80% quartz), natural Gorleben sediment
  • Elements: Eu3+,UO22+
  • Element concentration: 10-5 mol L-1
  • Ligands: SO42-, HCO3-
  • Competing cations: Ca2+, Al3+, Mg2+
  • pH: 3.5 - 5.5
  • Background electrolyte: NaClO4, Na2SO4, artificial groundwater

 

 

References:

Klein, C., The 22nd edition of the manual of mineral science, John Wiley and Sons, Inc., ISBN 0-471-25177-1, (2002).

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).