Influence and limitations of cation exchange processes of organic cations with different valence under geothermal boundary conditions - GEOCAT

拟议的工作将有助于通过进行系统的调查来进一步了解有机阳离子的吸附过程。主要集中在阳离子交换过程的基本机制及其与选定边界条件的依赖关系。特别要考察竞争无机阳离子和温度对交换平衡的影响。此外，计划中的工作应提供有关阳离子交换作为相关传输过程的竞争无机阳离子的最高(地热)温度和最大浓度(离子强度)的信息。为此，应对五种选定和定义的有机阳离子在德国北部储集层岩石材料上的吸附进行实验研究，并通过改变相关边界条件(离子强度、离子类型、温度)进行比较。另一方面，应深入研究有机阳离子与无机阳离子Na+、Ca~(2+)对有效交换点的竞争。另一方面，应测试和量化有机阳离子交换可能存在的温度依赖性。吸附行为的表征将在具有受控边界条件的柱实验中进行。

The proposed work shall contribute to the further understanding of the sorption processes of organic cations by conducting systematic investigations. The main focus is on the mechanismn of the underlying cation exchange processes and their dependences from selected boundary conditions. Especially, the role of competing inorganic cations and temperature on the exchange equilibrium shall be investigated. Furthermore, the planned work shall provide information on the maximum (geothermal) temperatures and maximum concentrations of competing inorganic cations (ionic strength) where cation exchange stays a relevant transport process.For this purpose, the sorption of five selected and defined organic cations onto a Northern German reservoir rock material shall be investigated experimentally and compared by varying relevant boundary conditions (ionic strength, ion type, temperature). On the on hand, the competition of organic cations with the inorganic cations Na+ and Ca2+ for the available exchange sites shall be studied intensively. On the other hand, the possible temperature dependence of the cation exchange of organic cations shall be tested and quantified. The characterization of the sorption behaviour will be carried out in column experiments with controlled boundary conditions.