Model membrane contamination

Gale, R.W. 1998, Three-compartment model for contaminant accumulation by semipermeable membrane devices. Environ. Sci. Technol. 32 2292-2300. 

In future work, more contamination modeling is needed, especially to account for the effect of different types of contaminants, such as anion and cation contaminants, on cell performance. In reality, of course, multiple contaminants are often the case, so a multicontaminant model needs to be developed that will take into accoimt both anode and cathode contaminants, as well as membrane contamination. 

In this chapter, where possible, we will use the definitions contained in Electrochemical Systems, 3 ed. (Newman and Thomas-Alyea [25]). We will discuss membrane contaminant models in one space dimension and time, which is sufficient to highlight all the major effects, but is readily extendable to two or three dimensions. In general, positive ionic current density, denoted by / in A/cm, will flow from left to right. We denote distance by 2 in absolute units (cm) and by x in scaled units. If L is the membrane thickness, X = z/L. 

Another consequence of membrane contamination by cationic impurity can be a decrease in the limiting current on polarization curve measured at high contamination levels. Due to proton deficiency at the cathode, the ORR current may become limited by diffusion of protons, but not oxygen diffusion through the CCL. This effect observed in experimental systems (Uribe et al, 2002 Halseid et al, 2006b) was qualitatively described using model assumptions proposed by Kienitz et al. (2009). 

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