Transport properties of charge-mosaic membranes I. Theoretical models

Charge-mosaic membranes are currently being considered for a number of practical applications, most notably "piezodialysis" desalination. In Part I of this series the properties of the charge-mosaic are subjected to a nonequilibrium thermodynamic analysis, with emphasis on the role of the electrical resistance in the solutions bathing the membrane. Four regimes of operation are delineated by the analysis: (i) membrane control, (ii) solution control, (iii) co-ion leakage control, and (iv) polarization control. For a charge-mosaic operating in the regime of membrane control, the "complete" phenomenological coefficients are essentially concentration-independent, hence the flows may be expressed as linear functions of the global forces. If the membrane operates instead in the regime of solution control, the relationships are not linear but the coefficients are still directly calculable.