XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
287
T5: P–7
Sonically prepared Fe-MFI and Fe-USY zeolites as catalysts
for DeNO
x
processes
Łukasz Kuterasiński
1,2
, Przemysław Jodłowski
1
, A. Dziedzicka
1
,
Roman Jędrzejczyk
3
, and Damian Chlebda
4
1
Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska
24, 31-155 Cracow, Poland, e-mail: nckutera@cyf-kr.edu.pl
2
Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, ul.
Niezapominajek 8, 30-239 Cracow, Poland
3
Malopolska Centre of Biotechnology, Gronostajowa 7a, 30-387 Cracow, Poland
4
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Cracow, Poland
The presence of hazardous pollutants in air is one of the problems associated directly with
environmental protection. Due to the solar radiation nitrogen oxides (NO
x
) react and form the
so-called photochemical smog, and have a negative influence on health and human life. One of
the possible way of nitrogen oxides removal is the selective catalytic reduction (SCR De-NO
x
)
[1]. The aim of this paper was to study sonochemically prepared Fe-MFI and Fe-USY type
zeolite as catalysts for selective catalytic reduction of NO
x
. Ultrasonic irradiation of aqueous
iron nitrate solution causes acoustic cavitation leading to bubble collapse and formation of
intense and short-term local heating and high pressures. These effects facilitate incorporation of
Fe species into zeolite structure. MFI and USY zeolites were sonicated in situ at 20oC for 20
min in an 0.5 mM aqueous solution of Fe(NO
3
)
3
·9H
2
O. For comparison, ion-exchanged zeolites
were also obtained. Prepared catalyst samples were characterized by various methods such as:
AAS, XRD and BET. Sorption and acidic properties of the studied samples were measured by in
situ IR methods using NH
3
, CO and NO as a probe molecules. Catalytic studies of selective
reduction of NO with ammonia were performed in a fixed-bed quartz microreactor. The reactant
concentrations were continuously measured using a quadrupole mass spectrometer (Prevac)
connected directly to the reactor outlet. XRD analysis confirmed pure MFI and USY type phase
of the studied catalysts. Acidity measurements (NH
3
-IR, CO-IR) in all cases indicated the
presence of Brønsted and Lewis acid sites. In case of MFI catalysts, lower concentration of the
latter type of acid centres corresponds to smaller Fe content in this type of zeolite in comparison
with USY. The type of modification of MFI and USY zeolite exhibited small differences in their
acidic properties. Sonicated zeolites exhibited somewhat higher either protonic or aprotonic
acidity.
Acknowledgment
The Project was financed by the National Science Centre Poland based on the decision No
2015/17/D/ST8/01252 and partly within National Centre for Research and Development No LIDER/204/L-
6/14/NCBR/2015.
References
[1] Z. Sarbak, Catalysis in environmental protection, AMU, Poznań/Poland, 2004, pp. 99–105, ISBN 83-
232-1346-1.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
288
T5: P–8
Spectroscopic studies of modified synthetic zeolites ZSM-5
and mordenite
Kamila Brylewska
1,2
, Magdalena Król
1
, Tomasz Bajda
3
, and Włodzimierz Mozgawa
1
1
Faculty of Materials Science and Ceramics, AGH University of Science and Technology, al.
Mickiewicza 30, 30-059 Krakow, Poland, e-mail: kamilaaa@agh.edu.pl
2
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland
3
Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and
Technology, al. Mickiewicza 30, 30-059 Krakow, Poland
Zeolites are widely applied in catalysis and environmental protection owing to their unique
sorptive, molecular-sieve, ion-exchange and catalytic properties. The structure of crystalline,
microporous aluminosilicates features arranged [SiO
4
] and [AlO
4
] tetrahedrons. Zeolites are often
modified, which allows hierarchical materials with a mesopore system to be obtained while
maintaining crystallinity. Modification yields materials with a highly developed surface area, which
results in better sorption capacity. Two types of modifications can be performed: "bottom-up" and
"top-down". The first type involves the synthesis of zeolites with the use of organic templates. The
mesopore system is generated as early as during synthesis, and allows interparticular mesoporosity to
be achieved. The second approach is based on post-synthesis modification, including demetalation
processes (desilication, dealumination, or a combination of both methods). Desilication involves the
selective removal of silicon cations from the zeolite framework and is carried out in an alkaline
environment. Dealumination involves the removal of aluminum cations in an acidic solution.
Zeolites are environmentally friendly materials that are used as sorbents of heavy metal cations.
Many studies [1, 2] have demonstrated that zeolites are characterized by high capacity, and are
therefore used to remove heavy metals from aqueous solutions via their immobilization.
The aim of the presented research was to investigate the influence of the generated system of
mesopores on the sorptive properties of synthetic zeolites. Two zeolites that belong to the structural
unit 5-1 [3] were investigated: ZSM-5 zeolite and mordenite. The studied zeolites were modified with
solutions of inorganic and organic hydroxides, and they were used to perform the sorption of selected
heavy metal cations (Pb
2+
, Cd
2+
, Ni
2+
, and Cr
3+
) ions. The following methods were used: XRF
(chemical composition), XRD (phase composition), AAS (the concentrations of analyzed ions in
aqueous solutions before and after sorption), IR and Raman spectroscopy (structural studies), and
BET (surface area).
The obtained results show that it is possible to generate a system of mesopores by means of the
proposed method. The conducted structural and textural investigations showed that modification
enhanced the mesoporosity of the surface while maintaining the microporous character of the
modified materials. The sorption of cations resulted in a slight change in the intensity and position of
the IR bands caused by the introduction of heavy metal cations was connected with ring bands. The
type of cation and zeolite also affected the intensity and position of these bands. The cation-exchange
capacity and the predominance of a particular sorption mechanism were dependent on the type of
Si/Al ratio and the concentration of cations in the insert solution. It was shown that the investigated
zeolites can find application as sorbents of heavy metals.
Keywords: zeolites; heavy metal cations; IR spectroscopy
Acknowledgments
This work was financially supported by the National Science Centre in Poland as part of grant no.
2016/21/N/ST8/01332.
References
[1] W. Mozgawa, T. Bajda, Phys. Chem. Miner. 31 (2005) 706.
[2] S. Tangkawanit, K. Rangsriwatananon, A. Dyer, Microporous Mesoporous Mater. 79 (2005) 171.
[3] Database of Zeolite Structures: International Zeolite Association.
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