Please use this identifier to cite or link to this item: http://hdl.handle.net/10773/37000
Title: Design of alumina monoliths by emulsion-gel casting: understanding the monolith structure from a rheological approach
Author: Nayak, Nayan
Vitorino, Nuno
Frade, Jorge R.
Kovalevsky, Andrei V.
Alves, Vitor D.
Crespo, João G.
Portugal, Carla A.M.
Keywords: Alumina monoliths
Emulsion-gel casting
Viscoelastic properties
Porous structure
Chromatography
Issue Date: 5-Nov-2018
Publisher: Elsevier
Abstract: Multimodal porous cellular alumina structures (monoliths) were prepared by an emulsion-gel casting technique using eco-friendly and inexpensive lipids such as corn oil, castor oil, margarine and their mixtures as the dispersed phase. The monoliths obtained showed good mechanical stability, exhibiting compressive strengths in the range of 8–50 N·mm−2. Mercury intrusion porosimetry analysis showed that the monoliths produced presented porosities ranging from 28% to 60% and average pore sizes within 0.2–3.2 μm. The formation of the porous networks was interpreted based on combined droplet coalescence, flocculation and Ostwald ripening effects. The presence of such effects along the emulsion storage time led to changes in their viscoelastic and morphological properties, which were found to correlate with structural descriptors of monoliths after sintering (e.g. average pore sizes and porosity). These correlations open up the possibility to anticipate the final structure of the monoliths and adjust emulsion-gel conditions to produce customized cellular structures with fine-tuned porosities and pore sizes, envisaging their application in membrane processes or chromatography.
Peer review: yes
URI: http://hdl.handle.net/10773/37000
DOI: 10.1016/j.matdes.2018.07.017
ISSN: 0264-1275
Appears in Collections:CICECO - Artigos



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