Atomic sieve theory

Among the many colloidal materials he studied was copper-ferrocyanide, which is formed as a gelatinous precipitate when copper sulfate is mixed with K ferrocyanide. The semipermeable properties of a membrane made of copper-ferrocyanide gel was discovered by Moritz Traube, who proposed the atomic sieve theory to explain semipermeability. Osmotic studies of Wilhelm Pfeifer provided the foundation for van t HofTs law of osmosis ... 

The answer to the first question is as follows the basis for the impermeability to a solute like sucrose is the size-dependent reduction of solubility and of diffusion coefficient in the polarized water and not that of a mechanical sieve as postulated originally by Traube in his atomic sieve theory, which was disproved and then repeatedly resurrected. ... 

---