Electrodialytic Demineralization Using Permselective Membranes

Abstract

Equations were derived for the energy consumption and production rate in electrodialytic demineralization, based on a simple empirical relation between the apparent compartment pair resistance and the electrolyte concentration in the desalting stream. The equations are independent of the compartment dimensions parallel to the membranes and of flow velocity. Special attention is given to the detrimental effect of water transport and an "over-all efficiency" is introduced which covers the nonideality of the membranes, salt diffusion, and water transport. The equations are compared with experimental results.

Concertration Polarization on Ion Exchange Resin Membranes in Electrodialytic Demineralization

“…For higher flow velocities they then established a correlation between qim and the functionally unrelated C()utiet, which correlation was concluded to be independent of v (the correlation with C"utJet is unfortunately limited to one specific length of desalting path). This independence is not found, however, when their data are correlated (Table I) using the In mean electrolyte concentration in the dialyzate, which is related to the average current density (16,22,28).…”