4.5. Osmotic pressure measurement
The osmotic pressure was measured for different concentration
ratios between one high-solute fluid (in matrix) and another lowsolute fluid (in fracture). The filter mesh cloth was treated by 0.60 mol/L membrane-forming materials. The relation between
osmotic pressure and concentration ratio was shown in Fig. 8. The
osmotic pressure increases with the increase of concentration ratio, which closely fit the theoretical value.