Osmotic model of clay swelling

Figure 8.11, Osmotic model of clay swelling (a) and clay shrinking (b). The left chamber contains clay and is separated from the right chamber (containing salt...

An osmotic model of clay swelling can be defended by the fact that the surface O... 

It can be inferred from the osmotic model of clay swelling (discussed in the previous section) that any influence on the clay-water system that lowers the free energy of water in the aqueous phase will reduce clay swelling. As seen earlier, high salt... 

Transport of salt and water into a capsule was considered in [3], Osmotic swelling of the capsule was assumed to be due to Donnan equilibrium between the salt solution outside the capsule and the interior solution which also contained polyelectrolyte molecules. The polyelectrolyte was unable to pass through the membrane which formed the wall of the capsule, but salt could pass freely. A model similar to that used for the clay membrane predicts two relaxation rates, only one of which was observed in experiments in which the salt concentration was varied in the external reservoir [4],... 

This swelling model does not apply to clays with mostly divalent and polyvalent cations on their exchange sites these clays show the hydration stage of expansion but not the osmotic one. The explanation for their behavior is found in the next section. 

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