Conference Presentation (Plenary/Keynote)

FZJ-2023-03849

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Thermodynamics of sorption of low molecular weight organic compounds to minerals

Konrad, A. (Corresponding author) ; Stutz, K. ; Lang, F. ; Hofmann, D.FZJ* ; Mulder, I. ; Siemens, J.

2023

Abstract: Mineral-induced stabilization is an important control of organic matter turnover in soils. However, it is still unknown i) how strongly does a molecule bind to a mineral surface and ii) how much energy is required to convert this formerly stabilized organic matter into a (dissolved) substrate. In order to address these questions, we developed an isothermal titration calorimetric method to assess the thermodynamics of the interaction between low molecular weight organic compounds and model soil minerals. We have selected organic acids which differ in polarity and degree of oxidation and have used kaolinite, illite and goethite as model minerals . The presentation will outline isothermal titration calorimetry as a method for assessing sorption reactions and relate the derived thermodynamic parameters, i.e. sorption enthalpy (H) and Gibbs free energy (G), of the sorption of low molecular organic weight compounds to their (de)sorbability and sorption hysteresis.

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 2173 - Agro-biogeosystems: controls, feedbacks and impact (POF4-217) (POF4-217)
2. DFG project 465123895 - Sorptionsthermodynamik und Aggregierung als Kontrollfaktoren für mikrobielle Substratverwertung und Mineralisierung (465123895) (465123895)

Appears in the scientific report 2023

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