XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
64
T1: O–22
Effect of thermal processing on the structural characteristics
of fly ashes
Wojciech Wons
1
, Karol Rzepa
1
, Manuela Reben
1
, and Paweł Murzyn
1
1
Faculty of Materials Science and Ceramics, AGH University of Science and Technology, al.
Mickiewicza 30, 30-059 Cracow, Poland, e-mail: krzepa@agh.edu.pl
This work investigated the course of fly ashes glassy phase crystallization in terms of
structural and thermal changes. On the basis of XRD studies the olivine and plagioclases phases
are formed after the second step of the heat treatment. XRD/Rietveld analysis confirmed
increased amount of mullite. The occurrence of crystallizing phases depends on the chemical
composition of fly ash. It was observed that under the heat treatment of fly ashes with a small
amount of modifying oxides a larger mullite superstructure appeared, what does not favor the Ca
rich plagioclases formation. The structural changes upon the heat treatment of fly ashes were
studied by means of 27 Al MAS NMR and FTIR spectroscopy. On the basis of NMR studies it
has been confirmed that aluminum ions in devitrified glassy phase occurred only in the
tetrahedral positions. Due to lack of Al
3+
the mullite superstructure formation and the formation
of a new crystalline phases (plagioclases) are competitive reactions.
Keywords: fly ash; mullite; plagioclase; olivine; crystallization process
References
[1] S.M. Shaheen, P.S. Hooda, C.D. Tsadilas, Opportunities and challenges in the use of coal fly ash for
soil improvements A review, J. Environ. Manag. 145 (2014) 249.
[2] P. Kunath-Fandrei, G. Losso, P. Hildmann, B. Schneider, H. Jäger, Am. Mineral. 83 (1998) 1266.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
65
T1: O–23
Sol-gel-derived bioactive glasses doped with L-ascorbic acid
Marta Szalkowska
1
, Beata Borak
1
, Anna Łukowiak
2
, Maciej Ptak
2
,
Bartosz Babiarczuk
1
, and Justyna Krzak
1
1
Department of Mechanics, Materials Science and Engineering, Wroclaw University of Science and
Technology, Wroclaw, Poland, e-mail: justyna.krzak@pwr.edu.pl
2
Institute of Low Temperature and Structure Research, PAS, Wroclaw, Poland
Bioactive glasses are biocompatible materials which in biological conditions (real or
simulated) are capable to form on the glass surface a layer of hydroxycarbonate apatite –
compound which is a natural component of bones. They are used in implantology, for example,
to enable to bind metallic surface with bone. Sol–gel-derived glasses are also ideal as carriers of
active compounds.
In the reported studies, the vitamin-doped bioglasses are not extensively described.
Therefore, it was interesting for authors to study, among others, the glasses doped with L-
ascorbic acid (vitamin C). This is a pharmacologically active compound that has a number of
beneficial properties, such as healing of wounds and strengthening the body's resistance to
infection. This antioxidant also accelerates bone coalescence.
The authors presented the results of the functionalization of sol-gel silica-based glasses by L-
ascorbic acid. Due to the sol-gel oxides inactivity in relation to the dopant and also due to the
lack of destructive interaction with substrates, silica-based glasses seems to be the proper
matrices for organic active substance. By using proper synthesis conditions (catalyst, reagents
volumes and ratio), samples were prepared both in the form of nanoparticles and layers. For
both form of oxides spectrophotometric measurements were performed. The chemical structure
and composition of the materials were evaluated based on Raman and FTIR spectra. The
presence and release of L-ascorbic acid was controlled by the absorption measurements.
The results indicate that obtained oxides matrices have the effect of prolonging the release
time of used active substance (L-ascorbic acid).
Keywords: bioactive glass, L-ascorbic acid, sol–gel
Acknowledgment
This research was partly supported by the National Science Centre research grant No.
2016/22/E/ST5/00530 and by Ministry of Science and Higher Education Republic of Poland project No.
0401/0070/16.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
66
T1: O–24
The influence of ZrO
2
precursor type on the structure
of ZrO
2
-TiO
2
-SiO
2
gels and selected thin films
Anna Adamczyk
1
1
Faculty of Materials Science and Ceramics, AGH University of Science and Technology,
Al. Mickiewicza 30, 30-059 Cracow, Poland, e-mail: aadamcz@agh.edu.pl
The zirconia-silica materials posses valuable properties but usually are synthesized in high
temperature processes. The sol-gel method enables to obtain materials of the same properties but
in much lower temperatures. As the raw materials, tetraethyl orthosilicate TEOS Si(OC
2
H
5
)
4
and
titanium isopropoxide Ti(OC
3
H
7
)
4
as SiO
2
and TiO
2
precursors, respectively, were used.
Additionally, different ZrO
2
precursors were applied as: zirconium acetate Zr(OOC
2
H
3
)
4
,
zirconium n-propoxide Zr(OC
3
H
7
)
4
or zirconium tetrabutoxide Zr(OC
4
H
9
)
4
. All gels were of
the same molar ratio ZrO
2
:TiO
2
:SiO
2
= 0,.089 : 0.018 : 0.089 but synthesized with different
ZrO
2
precursors, organic and inorganic ones as mentioned above. Because every precursor of
titania, silica and zirconia has got different speeds of hydrolysis and polycondensation
processes, the synthesis was run under anhydrous conditions. All gels were then dried in air and
annealed at 500, 800 and 1200°C. In case to obtain thin films basing on one of the ZrO
2
precursors, zirconium n-propoxide Zr(OC
3
H
7
)was selected and two sols of different degree of
dilution but the same molar ratio of ZrO
2
: TiO
2
: SiO
2
as in gels, were prepared. Coatings were
deposited on steel substrate by dip coating technique. To improve mechanical properties and
adhesion, all coatings were annealed at 500°C in air.
For all samples, wide structural studies were carried covering FTIR spectroscopy, X ray
diffraction and SEM microscopy. The surface of thin films was imagined in AFM microscope to
estimate the roughness and particles size of samples. The results allowed to study the influence
of different type of ZrO
2
precursor on the structure and morphology of synthesized gels and thin
films. The special focus was put on the presence and stabilization of metastable tetragonal form
of ZrO
2
, which is advantageous because of its valuable properties. The preliminary studies of
hydrophilic/hydrophobic properties of thin films were undertaken by measurements of the
wetting angle values of samples.
a)
b)
Fig. 1. SEM images of ZrO
2
-TiO
2
-SiO
2
thin film obtained on steel, a) dried; b) annealed at 500oC in air.
Keywords: ZrO
2
-TiO
2
-SiO
2
system; sol-gel method; FTIR; X-ray diffraction; SEM, AFM
Acknowledgment
The financial support of the AGH University of Science and Technology, Grant No. 11.11.160.767.
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