Supported liquid membranes degradation mechanisms

Neplenbroek, A.M., Bargeman, D. and Smolders, C.A. (1992) Mechanism of supported liquid membrane degradation - emulsion formation. Journal of Membrane Science, 67, 133. 

Sulfuric acid was used for the pH adjustment of the aqueous feed solution (pH 1.5). However, the supported liquid membrane also removes sulfuric acid in the similar mechanism. Thus, the sulfuric acid competes with the chromic acid in the feed solution for complexation with the amine in the membrane phase. The extraction of sulfuric acid into the strip solution is not desirable since it degrades the quality of chromate recovered in... 

Figure 18.4. Transport of Pt from a smaller particle to a larger particle by coupled transport of Pt throu the liquid and/or ionomer and the transport of electrons through the carbon support when the Pt particles are in contact with electronically conducting carbon [32]. (Reproduced by permission of ECS— The Electrochemical Society, from Virkar AV, Zhou Y. Mechanism of catalyst degradation in proton exchange membrane fuel cells.)...

During dynamic tests with thermal, load, and shutdown-start-up cycling, the amount and the vapor pressure of the water product varies and formation of liquid water might be involved. In addition, the shutdown-start-up or/and temperature cycling cause thermal and mechanical stresses to the membranes and cell components as well as volume expansions and contractions of the acid in the MEAs. Another important mechanism of the cell degradation involved in these dynamic tests is the corrosion of carbon supports and growth of noble metal catalysts [10]. Some dynamic test results are summarized in Table 22.10. 

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