title: Hierarchical Porous Zeolite Structures for Pressure Swing Adsorption Applications.
abstract: Porous adsorbents with hierarchical structured macropores ranging from 1 to 100 μm are prepared using a combination of freeze casting and additional sacrificial templating of polyurethane foams, with a zeolite 13X powder serving as adsorbent. The pore system of the prepared monoliths features micropores assigned to the zeolite 13X particle framework, interparticular pores of ∼1-2 μm, lamellar pores derived from freeze casting of ∼10 μm, and an interconnected pore network obtained from the sacrificial templates ranging from around 100 to 200 μm with a total porosity of 71%. Gas permeation measurements show an increase in intrinsic permeability by a factor of 14 for monoliths prepared with an additional sacrificial templated foam compared to monoliths solely providing freeze casting pores. Cyclic CO2 adsorption and desorption tests where pressure swings between 8 and 140 kPa reveal constant working capacities over multiple cycles. Furthermore, the monoliths feature a high volumetric working capacity of ∼1.34 mmol/cm(3) which is competitive to packed beds made of commercially available zeolite 13X beads (∼1.28 mmol/cm(3)). Combined with the faster CO2 uptake showing an adsorption of 50% within 5-8 s (beads ∼10 s), the monoliths show great potential for pressure swing adsorption applications, where high volumetric working capacities, fast uptakes, and low pressure drops are needed for a high system performance.
authors.affiliation: Advanced Ceramics, University of Bremen , Am Biologischen Garten 2, 28359 Bremen, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Besser
authors.affiliation: Advanced Ceramics, University of Bremen , Am Biologischen Garten 2, 28359 Bremen, Germany.
authors.forename: Henrique Akira
authors.initials: HA
authors.lastname: Tajiri
authors.affiliation: Institute of Fluid Mechanics, Dresden University of Technology , George-Bähr-Straße 3, 01062 Dresden, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Mikolajczyk
authors.affiliation: Institut für Nichtklassische Chemie e.V and der Universität Leipzig , Permoserstraße 15, 04318 Leipzig, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Möllmer
authors.affiliation: Advanced Ceramics, University of Bremen , Am Biologischen Garten 2, 28359 Bremen, Germany.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Schumacher
authors.affiliation: Institute of Fluid Mechanics, Dresden University of Technology , George-Bähr-Straße 3, 01062 Dresden, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Odenbach
authors.affiliation: Institut für Nichtklassische Chemie e.V and der Universität Leipzig , Permoserstraße 15, 04318 Leipzig, Germany.
authors.forename: Roger
authors.initials: R
authors.lastname: Gläser
authors.affiliation: Advanced Ceramics, University of Bremen , Am Biologischen Garten 2, 28359 Bremen, Germany.|Centre for Materials and Processes (MAPEX), University of Bremen , Bibliothekstraße 1, 28359 Bremen, Germany.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kroll
authors.affiliation: Advanced Ceramics, University of Bremen , Am Biologischen Garten 2, 28359 Bremen, Germany.|Centre for Materials and Processes (MAPEX), University of Bremen , Bibliothekstraße 1, 28359 Bremen, Germany.
authors.forename: Kurosch
authors.initials: K
authors.lastname: Rezwan
keywords: CO2 capacity; CO2 uptake; freeze casting; gas permeation; hierarchial porous structure; sacrificial template; volumetric working capacity; zeolite 13X