An electrical impedance spectroscopic (EIS) study on transport characteristics of ion-exchange membrane systems

Study of the effects of the applied current regime and the concentration of chromic acid on the transport of Ni2+ ions through Nafion 117 membranes

“…As expected, the values of R 1 decrease for increasing electrolyte concentrations, which is related to the increasing number of mobile ionic species being transported through the diffusion boundary layers and the membrane phase. Similar results were also obtained by other authors, which indicated that the significant increase in the resistance of the membrane system observed for diluted solutions was principally due to the contribution of the diffusion boundary layers [7,8] …”

“…The membranes were soaked several times with abundant water during 24 h in order to remove the traces of metals that are not associated with the fixed charges of the membrane. This method is usually known as the many-stage desorption method [7]. The resulting soak solutions were collected and the concentration of metals was measured by means of Atomic Absorption Spectrometry (AAS).…”

Interface resistances of anion exchange membranes in microbial fuel cells with low ionic strength

“…Current-voltage curves and impedance spectra were obtained for the AEMs in 10-or 100 mM PB solutions using a twocompartment cell (Choi et al, 2002;Park et al, 2006). Note that the type of two-compartment cell used here is different from the MFC, but was adopted because it is ideal for determining ion-transport resistance (O'Hayre et al, 2006).…”

“…Note that the type of two-compartment cell used here is different from the MFC, but was adopted because it is ideal for determining ion-transport resistance (O'Hayre et al, 2006). The cell was composed of two equal-volume (150-cm 3 ) compartments, and an AEM (1-cm diameter) was placed in the circular hole (area of 0.785 cm 2 ) between the compartments, as described elsewhere (Choi et al, 2002;Park et al, 2006). Direct and sinusoidal alternating currents were then supplied to a pair of Platinized titanium electrode at a scanning rate of 1 A/s to generate current-voltage curves, which gave a frequency range of 10 +6 to 10 −3 Hz for measuring the impedance spectra using a potentiostat/galvanostat (AutoLab, Model PGSTAT 30, Netherlands) (Park et al, 2006).…”

“…The resistances of the electric-double layer and diffusion boundary layer increased with lower electrolyte concentration (Długołęcki et al, 2010b), although changes in turbulence may also have influenced the diffusion boundary layer. A study using electrochemical impedance spectrometry (EIS) found that the ion-transport resistance through membranes consisted of resistances from the membrane itself, the electric-double layer at the membrane surface, and the diffusion boundary layer (Lee et al, 2008;Park et al, 2006). Thus, interface resistances from the electric double layer and diffusion boundary layer seem to have strong influences on internal resistance with low electrolyte concentrations.…”