Fine-tuning of effective pore size of microporous materials is necessary to achieve precise molecular sieving properties. Herein, we demonstrate that room temperature ionic liquids can be used as cavity occupants for modification of the microenvironment of MOF nanocages. Targeting CO2 capture applications, we tailored the effective cage size of ZIF-8 to be between CO2 and N2 by confining an imidazolium-based ionic liquid [bmim][Tf2 N] into ZIF-8's SOD cages by in-situ ionothermal synthesis. Mixed matrix membranes derived from ionic liquid-modified ZIF-8 exhibited remarkable combinations of permeability and selectivity that transcend the upper bound of polymer membranes for CO2 /N2 and CO2 /CH4 separation. We observed an unusual response of the membranes to varying pressure, that is, an increase in the CO2 /CH4 separation factor with pressure, which is highly desirable for practical applications in natural gas upgrading.

Membranes derived from metal-organic frameworks present a new category of molecular sieves. As demonstrated by Y. Li., J. Caro et al. in their Communication on page 548 ff., a supported zeolitic imidazolate framework (ZIF-7) membrane exhibits high H 2 selectivity by serving as a molecular sieve. The picture shows the synthesis of the ZIF-7 membrane which includes surface seeding and microwave-assisted solvothermal synthesis.

Molekularer Seiher: Das ultramikroporöse zeolithische Imidazolatgerüst ZIF‐7 wurde bezüglich seiner Eignung zur Gastrennung an Membranen untersucht. Dazu wurde es mithilfe von mikrowellengestütztem gezieltem Wachstum auf einen asymmetrischen Aluminiumoxidträger aufgebracht. Die erhaltene Membran war thermisch stabil und als Molekularsieb hoch H2‐selektiv.

Fine‐tuning of effective pore size of microporous materials is necessary to achieve precise molecular sieving properties. Herein, we demonstrate that room temperature ionic liquids can be used as cavity occupants for modification of the microenvironment of MOF nanocages. Targeting CO2 capture applications, we tailored the effective cage size of ZIF‐8 to be between CO2 and N2 by confining an imidazolium‐based ionic liquid [bmim][Tf2N] into ZIF‐8’s SOD cages by in‐situ ionothermal synthesis. Mixed matrix membranes derived from ionic liquid‐modified ZIF‐8 exhibited remarkable combinations of permeability and selectivity that transcend the upper bound of polymer membranes for CO2/N2 and CO2/CH4 separation. We observed an unusual response of the membranes to varying pressure, that is, an increase in the CO2/CH4 separation factor with pressure, which is highly desirable for practical applications in natural gas upgrading.

No abstract

Mixed ionic-electronic conducting (MIEC) membranes have gained growing interest recently for various promising environmental and energy applications, such as H 2 and O 2 production, CO 2 reduction, O 2 and H 2 separation, CO 2 separation, membrane reactors for production of chemicals, cathode development for solid oxide fuel cells, solar-driven evaporation and energy-saving regeneration as well as electrolyzer cells for powerto-X technologies. The purpose of this roadmap, written by international specialists in their fields, is to present a snapshot of the state-of-the-art, and provide opinions on the future challenges and opportunities in this complex multidisciplinary research field. As the fundamentals of using MIEC membranes for various applications become increasingly challenging tasks, particularly in view of the growing interdisciplinary nature of this field, a better understanding of the underlying physical and chemical processes is also crucial to enable the career advancement of the next generation of researchers. As an integrated and combined article, it is hoped that this roadmap, covering all these aspects, will be informative to support further progress in academics as well as in the industry-oriented research toward commercialization of MIEC membranes for different applications.

Dynamische Öffnungen und eine superhydrophobe Oberfläche begründen die außergewöhnliche Fähigkeit des Metall‐organischen Gerüsts ZIF‐8 zur selektiven Adsorption von Alkoholen. In eine Polymermatrix eingebettete ZIF‐8‐Nanopartikel wirken als bevorzugte Permeationspfade für organische Verbindungen, was in der effizienten Gewinnung von Bioalkoholen aus Fermentationsgemischen genutzt werden kann (siehe Bild).

No abstract