MAPEX Research Highlights

Hierarchical Porous Zeolite Structures for Pressure Swing Adsorption Applications

Benjamin Besser, Henrique Akira Tajiri, Gerd Mikolajczyk, Jens Moellmer, Thomas C. Schumacher, Stefan Odenbach, Roger Glaeser, Stephen Kroll and Kurosch Rezwan.

ACS Applied Materials & Interfaces (2016) 8, 3277-3286.

doi:10.1021/acsami.5b11120

Porous adsorbents with hierarchical structured macropores ranging from 1 to 100 mu m 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 similar to 1-2 mu m, lamellar pores derived from freeze casting of similar to 10 mu m, and an interconnected pore network obtained from the sacrificial templates ranging from around 100 to 200 mu m 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 similar to 1.34 mmol/cm(3) which is competitive to packed beds made of commercially available zeolite 13X beads (similar to 1.28 mmol/cm(3)). Combined with the faster CO2 uptake showing an adsorption of 50%-within 5-8 s (beads similar to 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.

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