Selective permeability of grafted nylon-6 membranes: 2. Potassium chloride permeation in acrylic acid grafted membranes

The permeation of potassium chloride through γ-irradicated nylon-6 membranes grafted with acrylic acid (AA) was investigated. The permeability of potassium chloride increases with increasing levels grafting in the membrane. It was found that the theory of permeation of electrolyte through ionic membranes (derived from the phenomenological equation) was applicable to the permeation of potassium chloride through AA-grafted membrane with high levels of grafting. The effective concentration of fixed charge determined by the Donnan membrane equilibrium exhibited almost the same value in the grafted membrane regardless of the levels of grafting. It was found that a tortuosity factor was dominant through affecting the permeation of KCI through the membrane. This may be considered as an interference factor in a homogeneous membrane.