Potential Measurements for Selectivity Determinations of Polycarbonate Membranes Bounded by MgCl2Solutions

The emf of the cell chloride selective electrode/MgCl2(N 1)/membrane/MgCl2(N 2)/chloride selective electrode, containing a polycarbonate membrane, has been measured at 20, 30, 40, and 50°C. The membranes studied had pore diameters ranging from 5.0 to 0.03 μm, and bounding solutions concentrations vary from 2 × 10−4 to 10−1 equiv/dm3. Apparent transport numbers of cation and permselectivities, deduced from emf values, are given. Results show that polycarbonate membranes are permselective to Mg2+ when the concentration of bounding solutions is low.