Development of thin anion-exchange pore-filled membranes for high diffusion dialysis performance

• Thin pore-filled membranes are prepared for diffusion dialysis (DD) application.
• The thin membranes possess excellent mechanical and electrochemical properties.
• The membrane surface is also modified by introducing thin dense polypyrrole layer.
• The polypyrrole layer results in the significant improvement of DD performances.

Pore-filled anion-exchange membranes (PFAEMs) with a thickness of about 25 μm have been prepared using porous polyethylene substrates and tested for diffusion dialysis (DD) application. The membranes possess strong mechanical properties (tensile strength and elongation at break of 125.8 MPa and 76.2%, respectively) as well as excellent electrochemical characteristics such as low electrical resistance (<0.4 Ω cm2), high anion transport number (>0.97), and high fraction of conductive region on the membrane surface etc. Moreover, in order to further improve the diffusion dialysis performance of the PFAEMs, the surface of PFAEMs was modified by introducing a thin polypyrrole layer with good affinity to anions. As a result, the PFAEMs exhibited excellent DD performances (high acid permeability and selectivity) superior to that of commercial membrane (i.e. Neosepta-AFX, Astom Corp., Japan) by the surface-modification.