Impedance characteristics and electrical double-layer capacitance of composite polystyrene–cobalt–arsenate membrane
Abstract
In continuation of our previous work with composite polystyrene–cobalt–arsenate (PS–Co–As), we
further extended impedance measurements. All calculations reported were extracted from experiments
carried out in the frequency range of 1–5 kHz and different concentrations (0.0001 c(M) 1) of KCl and
NaCl at isothermal temperature (25 0.1 8C). The membrane capacitance and resistance measurements
were observed to depend on the concentration and the applied frequency of the electrolyte. The observed
capacitances and resistances were used to calculate the membrane resistances (RM), capacitance (CM),
reactance (XX), and also derive the impedance (Z). At higher frequencies, the capacitances became low and the
impedance decreased with increasing frequency with a corresponding increase in the measured phase angle.
On the other hand at the highest frequencies attainable, the phase angle became low. At low frequencies, the
phase angle was become independent of the cation, while the impedance showed a clear dependence. The
diffused double-layer polarization charge on the geometric capacitor played important role by affecting the
overall membrane capacitance. The applied frequencies affected the double-layer capacitance due to the
movement of ions across the membrane. At the membrane–electrolyte interface, the electrical double-layer
was influenced in addition to being controlled by the transport of ions.
URI
http://hdl.handle.net/10394/14305http://www.journals.elsevier.com/journal-of-industrial-and-engineering-chemistry/