Porous geopolymer with k-based and na-based activator using teepol surfactant as foaming agent
Geopolymer technology is presented with the aim to introduce the materials that may be synthesized by alkali-activation of aluminosilicates. Highly porous geopolymers with homogenous microstructure were fabricated by gelcasting. The effects of surfactants on microstructure of porous geopolymer we...
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| Format: | Academic Exercise |
| Language: | English |
| Published: |
2015
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/18962/1/Porous%20geopolymer.pdf https://eprints.ums.edu.my/id/eprint/18962/ |
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| Summary: | Geopolymer technology is presented with the aim to introduce the materials that may
be synthesized by alkali-activation of aluminosilicates. Highly porous geopolymers
with homogenous microstructure were fabricated by gelcasting. The effects of
surfactants on microstructure of porous geopolymer were investigated. The synthesis
process of porous geopolymer was generated from meta kaolin, alkaline activator
solutions (K-based and Na-based) and Teepol surfactant as foaming agent. The role
of surfactant in this study is to stabilize the wet foams by decreasing the surface
tension of the system. The particle size and size distribution of the geopolymer foams
were adjusted by the control of surfactant content at 4 wt% and 10 wt% with
respect to total weight. The foams were evaluated only after heat treatment at 80°C,
which was conducted in order to complete the geopolymerization reactions. Lastly,
the sintering of porous geopolymer was done at 500°C, 700 °C and 900°C to
investigate the thermal cracks distribution of porous geopolymer. The porous
geopolymer was then characterized using SEM, FTIR, TGA and XRD. The results
showed that increasing surfactant content favors the adsorption at gas/liquid
interface, thereby promoting foaming. TGA analysis showed that the dehydroxylation
of kaolin occurs at temperatures above 450°C. The octahedral sheet loses water and
decomposed into disordered meta phase during dehydroxylation between 450°C and
800°C. In FTIR spectrum, OH stretching around 3700 cm-1 to 3620 cm-1 doublet was
shown to be the characteristic for the raw material, kaolin. The raw material contains
72 wt% kaolin, 27 wt% quartz and minor amount of other components in accordance
to XRD data. Overall, the morphology, strength and thermal resistance of the porous
geopolymer suggest that they could be employed as low cost replacement for highly
porous ceramics in applications such as catalysis supports, adsorption and
separation, filtration of hot gases and refractory insulation of furnaces. |
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