Types Of Ion Exchange Membranes Research Articles

The Steady-State Properties of Ion Exchange Membranes with Fixed Sites

The properties of the steady states of a system composed of two solutions separated by a quite general type of ion exchange membrane having fixed sites are derived as functions of the compositions of the solutions and of the difference of electric potential between the two solutions. These properties are evaluated with the restraints that the membrane is solely permeable to cations or anions, no flow of solvent occurs, and the solutions contain no more than two permeant ionic species, which are monovalent. Under the assumptions that the difference of standard chemical potentials of the permeant species and the ratio of their mobilities are constant throughout the membrane, even when the spacing of sites is variable, explicit expressions are derived for the electric current, individual fluxes, and concentration profiles. An unexpectedly simple dependence of these expressions upon distribution of sites is found.

Performance of fractional watt ion exchange membrane fuel cells

AbstractThe effect of design and operational variables on the performance of one type of hydrogen‐oxygen ion exchange membrane fuel cell has been studied. Only the results of cells based on a phenolsulfonic acid formaldehyde type of ion exchange membrane containing one type of reinforcement are described. Platinum, palladium, iridium, and rhodium are adequate electrode materials for room‐temperature operation. Performance of cells with platinum gauze current collectors bonded to the cell surfaces was only slightly better than that with external contacts about 1 cm. apart.Open circuit voltages range from 0.9 to 1.1 v. (theoretical 1.23) depending on the catalyst. The typical current at 0.5 v. is 30 ma./sq. cm. Better cells have delivered 80 ma./sq. cm. at 0.5 v. Life tests indicate that these cells can be expected to deliver a minimum of about 40 amp.‐hr./sq. cm., when operated in the load range 8.5 to 230 ohm sq. cm., before failure of the electrolyte owing to pinhole formation. Current efficiency is very nearly 100%. Cell performance vs. temperature in the range 0° to 85°C. shows a maximum at about 55°C.