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Browsing by Author Bachmann, J.

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  • BB

  • Iron Oxide Colloid Mobility as Affected by Solid Matrix Wetting Properties

    • Authors: Carstens, J.F.;  Advisor: -;  Participants: Bachmann, J.; Neuweiler, I. (2018)

  • Flow column results elucidated that decreasing sand wettability had no relevant effect on OMCG colloid mobility. In contrast, colloid retention increased with ionic strength in each type of sand packing. Classic DLVO interactions could predict trends in colloid retention by the respective characteristics of energy barriers and secondary minima. The extension with Lewis acid–base interactions in the XDLVO approach led to the prediction of significant short‐range (∼2 nm) attractive interaction energies between colloids and hydrophobized sand, which were not reflected by colloid breakthrough behavior. This was probably due to substantial energy barriers calculated for larger distances (∼...
  • BB

  • The Role of Matric Potential, Solid Interfacial Chemistry, and Wettability on Isotopic Equilibrium Fractionation

    • Authors: Gaj, M.;  Advisor: -;  Participants: Lamparter, A.; Woche, S.K.; Bachmann, J.; McDonnell, J.J.; Stange, C.F. (2019)

  • Additionally, we tested two natural soil samples to explore wettability effects. Samples were dried at temperatures between 40 and 550°C to produce chemically modified surface properties. All samples were spiked with water of known isotopic composition at different water contents. The isotopic signature was determined using the vapor‐bag equilibration method. The matric potential of each sample was measured with a soil water potential meter, the contact angle was determined with the sessile drop method, and the surface chemistry by X‐ray photoelectron spectroscopy. In addition to temperature and soil matric potential, the elemental composition has apparently some control on the equili...