The Effect of Pressure on Diffusion in Water and in Sulfate Solutions

Diffusion coefficients are presented as a function of pressure to 10 000 atmospheres for the following systems: THO−H2O 0∘−25∘−50∘;0.1 N H2S35O4 −0.1 N H2SO4 0∘−5∘−25∘−50∘;0.1 N Na2S35O4 −0.1 N Na2SO4 0∘−25∘−50∘;1.0 N Na2S35O4 −1.0 N Na2SO4 0∘−25∘−50∘;0.1 N K2S35O4 −0.1 N K2SO4 0∘−25∘−50∘.The results are interpreted in terms of the activation volume and the tetrahedrally coordinated structure of water. It is found that pressure tends to break down the structure, and in certain regions an increase in diffusion coefficient with pressure is noted. In the salt solutions the water structure is controlling with some added effects due to solvation and ionic interaction.