Cation fixation potassium

Since charged particles involve all these processes, including the formation of edge charges (Equations 2.3-2.5), first, the electric properties of interfaces have to be determined. A simple way to do so is the application of a support electrolyte in high concentration. The electric double layer, in this case, behaves as a plane and, as a first approach, the Helmholtz model, that is, the constant capacitance model, can be used (Chapter 1, Section 1.3.2.1.1, Table 1.7). It is important to note that the support electrolyte has to be inert. A suitable support electrolyte (such as sodium perchlorate) does not form complexes (e.g., with chloride ions, Section 2.3) and does not cause the degradation of montmorillonite (e.g., potassium fixation in the crystal cavities). In this case, however, cations of the support electrolyte, usually sodium ions, can also neutralize the layer charges ... 

Vermiculites. Vermiculites are 2 1 expanding minerals with a structure similar to micas (Table 7-4). They are considered to be derived from the alteration of micas (Douglas, 1977). Cation exchange capacity is high, as is the surface area. Potassium or NHj in solution tends to be strongly fixed by vermiculites. Upon fixation of these ions, the CEC decreases and the properties of vermiculite become like those of mica. In acid soil, hydroxy aluminum polymers can be fixed in the interlayer position to form an "island-like" structure (Jackson,... 

Hydromicas are authigenic minerals rather easily forming in a sedimentary environment. Fe-illites would be the analogs of glauconites in gradually salting-up basins. The out-flow of bottom waters and the fixation of the bivalent cations Ca and Mg " (in dolomite) in case of a relatively low concentration of the latter (sodic-calcic lakes) lead to the relative enrichment of these in potassium. The latter will then be fixed by the silicate compounds in solution leading to the synthesis of Fe-illites. In case... 

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