Fabrication and characterization of porous mullite ceramics derived from fluoride-assisted Metakaolin-Al(OH)3 annealing for filtration applications
Amanmyrat Abdullayev,
Celal Avcioglu,
Tobias Fey,
André Hilger,
Markus Osenberg,
Ingo Manke,
Laura M. Henning,
Aleksander Gurlo,
Maged F. Bekheet
Affiliations
Amanmyrat Abdullayev
Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institute of Materials Science and Technology, Technische Universität Berlin, 10623, Berlin, Germany
Celal Avcioglu
Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institute of Materials Science and Technology, Technische Universität Berlin, 10623, Berlin, Germany
Tobias Fey
Department of Materials Science and Engineering, Institute of Glass and Ceramics, University of Erlangen-Nürnberg, Erlangen, Germany; Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Nagoya, Japan
André Hilger
Institute of Applied Materials, Helmholtz Centre for Materials and Energy, Berlin, Germany
Markus Osenberg
Institute of Applied Materials, Helmholtz Centre for Materials and Energy, Berlin, Germany
Ingo Manke
Institute of Applied Materials, Helmholtz Centre for Materials and Energy, Berlin, Germany
Laura M. Henning
Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institute of Materials Science and Technology, Technische Universität Berlin, 10623, Berlin, Germany
Aleksander Gurlo
Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institute of Materials Science and Technology, Technische Universität Berlin, 10623, Berlin, Germany
Maged F. Bekheet
Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institute of Materials Science and Technology, Technische Universität Berlin, 10623, Berlin, Germany; Corresponding author.
In this work, polycrystalline mullite whiskers are synthesized by fluoride-assisted method from metakaolin and several aluminum-containing compounds such as γ-Al(OH)3, AlF3·3H2O, and α-Al2O3 (corundum). The mullite formation and crystallization are assessed both in ex situ and in situ synchrotron X-ray diffraction experiments under synthesis conditions. Polycrystalline mullite starts to form from metakaolin, Al(OH)3, and AlF3·3H2O reactants at 680 °C, whereas mullite does not form even at 1000 °C when corundum is used. Porous mullite ceracmics are fabricated at sintering temperatures between 1000 and 1700 °C and tested for water permeance. Scanning Electron Microscopy (SEM) and synchrotron X-ray tomography (μCT) reveal that ceramics are comprised of pore channels with an interlocked network of mullite whiskers. With competitive porosity (up to 63 %), compressive strength (up to 20 MPa), and pure water flux (up to 579 L/m2·h at 1 bar), fabricated mullite ceramics are promising candidates for water filtration and purification.
