Abstract
A weakly amphoteric polymer was prepared using silk fibroin. The salt permeability coefficient of the membrane was measured at various pH levels in the outer solution. The possibility of piezodialysis was discussed using phenomenological equations based on the non-equilibrium thermodyllamics. The hydraulic permeability coefficient lp was not affected by the pH. On the other hand, the reflection coefficient σ and the solute permeability coefhcient ω were affected by pH. At the isoelectric point, σ was at its minimum value and ω was at its maximum value. It is possible to change the solute permeability by controlling the pH in the outer solution and the state of the fixed charge groups.
