COMPETITIVE INTERACTIONS BETWEEN WATER AND ORGANIC-SOLVENTS ONTO MINERAL SOLID-SURFACES STUDIED BY CALORIMETRY

Investigations have been carried out on several systems to compare the strength of the solid/liquid interactions. Possible industrial implications for the results have guided the choice of the studied systems beeing mineral oxide/water and mineral oxide/pyridines systems. Immersional enthalpies of the solids in different solvents including water and pyridines as well as adsorption densities of pyridines from water onto solids have been measured. Each of these experiments proved that pyridines could be adsorbed preferentially to water on the studied solids. In order to establish if pyridine can also displace water from the oxide surface, immersion of the solid with preadsorbed water vapor in pyridine has been performed. The obtained results show a possible displacement of the water by the pyridine from the solid surface. The reverse experiment, i.e. immersion of the solid with preadsorbed pyridine vapor in water, has also been run showing that, apparently, water is able to displace pyridine from the solid surface.