In this comprehensive review, recent progress and developments on perfluorinated sulfonic-acid (PFSA) membranes have been summarized on many key topics. Although quite well investigated for decades, PFSA ionomers’ complex behavior, along with their key role in many emerging technologies, have presented significant scientific challenges but also helped create a unique cross-disciplinary research field to overcome such challenges. Research and progress on PFSAs, especially when considered with their applications, are at the forefront of bridging electrochemistry and polymer (physics), which have also opened up development of state-of-the-art in situ characterization techniques as well as multiphysics computation models. Topics reviewed stem from correlating the various physical (e.g., mechanical) and transport properties with morphology and structure across time and length scales. In addition, topics of recent interest such as structure/transport correlations and modeling, composite PFSA membranes, degradat...

New Insights into Perfluorinated Sulfonic-Acid Ionomers

This review highlights various aspects of current palladium membrane research and serves as a comprehensive bibliography covering palladium membrane preparation methods and applications. There are many promising uses for palladium membranes, although widespread use of the available technologies is constrained primarily by the high cost of palladium, lack of durability due to hydrogen embrittlement, and susceptibility to fouling. Various researchers in the field are tackling these problems and fabricating thinner palladium alloy composite membranes that better withstand contaminantion and thermal cycling. What has been accomplished to address these issues and the directions presently being explored are discussed.

Innovations in palladium membrane research

The separation of molecules with similar size and shape is an important technological challenge. For example, rare gases can pose either an economic opportunity or an environmental hazard and there is a need to separate these spherical molecules selectively at low concentrations in air. Likewise, chiral molecules are important building blocks for pharmaceuticals, but chiral enantiomers, by definition, have identical size and shape, and their separation can be challenging. Here we show that a porous organic cage molecule has unprecedented performance in the solid state for the separation of rare gases, such as krypton and xenon. The selectivity arises from a precise size match between the rare gas and the organic cage cavity, as predicted by molecular simulations. Breakthrough experiments demonstrate real practical potential for the separation of krypton, xenon and radon from air at concentrations of only a few parts per million. We also demonstrate selective binding of chiral organic molecules such as 1-phenylethanol, suggesting applications in enantioselective separation.

https://www.adamkewley.com/files/Adam-Kewley_Nature-Materials-Paper.pdf

Separation of rare gases and chiral molecules by selective binding in porous organic cages

Permeability, solubility and diffusivity of hydrogen isotopes in stainless steels at high gas pressures

Review of methane catalytic cracking for hydrogen production

Tritium diffusivity in crystal grain of Li2TiO3 and tritium release behavior under several purge gas conditions

The adsorption equilibria of Kr, Xe and N2, which are constituents of the off-gas from nuclear reprocessing processes, on representative adsorbents (Molecular Sieve 5A (MS5A) and activated charcoal) were studied. Adsorption experiments were conducted in the temperature range of 77 to 323 K using a packed bed column. The adsorption isotherms for the activated charcoal adsorbent were successfully correlated by the vacancy-solution model. The adsorption isotherms for the MS5A adsorbent were properly correlated by the Langmuir model and the vacancy solution model. The adsorption experiments for the binary component systems (Kr—Xe, Kr—N2 systems) were also performed, and the results suggest that the coexistence of Xe greatly inhibits the adsorption of Kr. The coexistence of large amounts of N2 was also found to inhibit the adsorption of Kr. The experimental results for the adsorption equilibrium of binary component systems on the activated charcoal adsorbent were well reproduced by the vacancy solution model w...

https://www.tandfonline.com/doi/pdf/10.1080/18811248.1999.9726272

Masabumi Nishikawa

Papers

Tritium diffusivity in crystal grain of Li2TiO3 and tritium release behavior under several purge gas conditions

Adsorption equilibria of krypton, xenon, nitrogen and their mixtures on molecular sieve 5A and activated charcoal

Tritium trapping capacity on metal surface

Release behavior of bred tritium from LiAlO2

Tritium inventory in a LiAlO2 blanket