Tuneable ion-selective inorganic membranes

A new type of ion-selective ceramic membrane with electrically tuneable selectivity is reported. The membrane consists of a conventional supported γ-alumina membrane with porous gold electrodes sputtered on both sides. An electrical potential difference can be applied over the electrodes. The transport of Cu2+ ions was investigated as a function of the applied field strength over the membrane and the copper concentration in the feed solution. It is shown that the transport rate can be tuned efficiently by the magnitude and direction of the field. This technology may find application in micro-fluidic devices such as micro total analysis systems.