Synthesis of ZSM-5 zeolite using Bayat natural zeolite as silica and alumina source Rohayati, Y. K. Krisnandi, and R. Sihombing
Citation: AIP Conference Proceedings 1862, 030094 (2017); doi: 10.1063/1.4991198 View online: http://dx.doi.org/10.1063/1.4991198 View Table of Contents: http://aip.scitation.org/toc/apc/1862/1 Published by the American Institute of Physics
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Synthesis of ZSM−5 Zeolite Using Bayat Natural Zeolite as Silica and Alumina Source Rohayati, Y. K. Krisnandi and R. Sihombinga) Department of Chemistry, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok 16424, Indonesia a)
Corresponding author:
[email protected]
Abstract. Zeolite ZSM-5 has been successfully synthesized from natural zeolite Bayat without further purification. The silica and alumina source are taken from the natural zeolite through submolten depolimerization method. Ludox 40% was used as additional silica source to reach Si/Al ratio of 32 in the starting gel and tetrapropylammonium hydroxide (TPAOH) was used as a structure directing agent (SDA). Synthesis was carried out hydrothermally with aging and crystallization temperature at 150°C. The as-synthesized zeolite was characterized with XRD, FTIR and SEM-EDX. The XRD patterns of the resulted synthesis showed diffraction peaks at 2θ = 7.9°- 8.8° (doublet peaks) and diffraction peaks at 2θ = 22°- 25° (triplet peaks) which are characteristic for ZSM-5 structure. The SEM image showed that the ZSM-5 zeolite from Bayat natural zeolite had morphology of hexagonal crystalls with some debris of impurities. The elemental analysis using EDX gave Si/Al molar ratio of 18.5. Keywords: natural zeolite, ZSM-5, submolten, depolimerization method
INTRODUCTION Zeolite is a crystalline aluminosilicate with a three-dimensional framework structure that forms uniform poresize. Because of its important chemical properties, this material has been applied in many industrial application such as selective absorbent, ion-exchange resin, and high activity catalyst [1]. In Indonesia, natural zeolite can be found in abundant quantity. But, because of its low purity, the utilization of this mineral is limited to low technology application. Due to the increase usage of zeolite, it is proposed to utilize silica and alumina that is exist in natural zeolite as Al and Si source to synthesize zeolite with high purity. The use of silica and alumina source from natural material such as natural zeolite, kaolin, fly ash and rice husk are being developed by many researchers [2-4]. One of zeolite type that has been widely used in industry is Zeolite Socony Mobil-5 (ZSM-5). ZSM-5 has high thermal stability, many acid sites, high selectivity, well adsorption property, and has high activity in certain catalytic conversion, mainly in isomerization, alkylation, and aromatization process [5]. Jiang et al. [6] has successfully synthesized ZSM-5 hydrothermally in acid solution using natural zeolite Palygorskite using TPABr as template at 180°C for 48 hours. ZSM-5 zeolite has also been successfully synthesized from natural alumina-silica source in alkaline solution through submolten systems [7]. In this work, we focused on synthesis of ZSM-5 zeolite using silica and alumina source from Bayat natural zeolite. Prior to the synthesis, depolimerized zeolite framework was carried out through submolten system in alkaline solution at temperature 523 K [2,7]. Synthesis of ZSM-5 was carried out through single template methods using tetrapropyl ammonium hidroxyde (TPAOH) as structure directing agent (SDA).
International Symposium on Current Progress in Mathematics and Sciences 2016 (ISCPMS 2016) AIP Conf. Proc. 1862, 030094-1–030094-4; doi: 10.1063/1.4991198 Published by AIP Publishing. 978-0-7354-1536-2/$30.00
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MATERIALS AND METHOD Materials: Natural zeolite used in this study was obtained from Bayat Klaten, Central Java, Indonesia with particle size distribution of 74 μm. Sodium hydroxide (Merck 99.9%), TPAOH 1M (Sigma Aldrich), Ludox 40wt.% (Sigma Aldrich), CH3COOH glacial (Sigma Aldrich), and deionized water were used in this experiment. All of the chemicals were purely analytical grade and used without any further purification. From the previous research, it was known that natural zeolite Bayat has Si/Al molar ratio in the range of 4-6 [4]. Depolimerized natural zeolite: Natural zeolite Bayat was depolimerized following the procedure carried out by Yue et al. [7]. The zeolite was immersed in alkaline solution made of NaOH pellets with molar ratio 1:1 in deionized water. The mixture was heated at 523 K for 2 hours. Synthesis of ZSM−5 zeolite: Depolimerized zeolite, distilled water, TPAOH and Ludox were mixed under vigorous stirring and aged at 373 K for 3 hours. The molar ratio of obtained was 64.34 SiO2 : 1 Al2O3 : 10.08 (TPA)2O : 3571.67 H2O [8]. After stirring at room temperature for 20-24 hours, the mixture was transferred into a teflon-lined stainless steel autoclave for further crystallization at 423 K for 144 hours. The product was then collected by filtration, washed and dried. ZSM-5 was then calcined at 823 K and characterized using XRD, SEM, EDS, and FTIR instruments.
RESULTS AND DISCUSSION At the beginning of synthesis process, natural zeolite was depolimerized using NaOH as a destructing agent through submolten technique at temperature 523 K to breakdown zeolite framework. Figure 1 shows FTIR spectra of natural zeolite and depolimerized zeolite, in which the peaks between 1350 and 1500 cm-1 only appeared in depolimerized zeolite, but not in natural zeolite. These are similiar to peaks NaSiO2 and NaAlO2 (from Sigma Aldrich) that are used as starting materials in the synthesis of ZSM-5 from pro analysis [11]. Furthermore, in the region between 500 and 650 cm-1, peaks for finger print of zeolite framework disappeared in depolimerized zeolite. This FTIR spectra confirm that the zeolite framework has been destructed, creating aluminate (AlO45-) and silicate (SiO44-) anions as monomers. In the synthesis of ZSM-5, tetra propylammonium hidroxyde (TPAOH) is used as a template for directing to MFI type structure. Figure 2 showed FTIR spectra of ZSM-5 before and after calcination. Before calcination, there are specific peaks at 2850 and 2960 cm-1, and 1350 and 1475 cm-1 that are assigned to C−H stretching and bending vibrations, respectively. These peaks show the presence of organic template in the crystal. Meanwhile, in FTIR spectra of ZSM-5 after calcination, those peaks disappeared, indicating that the organic template has been decomposed due to calcination process. Furthermore there are other specific peaks of alumina-silica framework at 950 to 1250 cm-1 (asymmetry stretching of T – O), 700 to 1100 cm-1 (symmetry stretching of T – O) and 500 to 650 cm-1 which are correlated to double ring from pentasyl framework composing the MFI type zeolite [9]. 5
3
Depolimerized Natural NaSiO2 p.a NaAlO2 p.a
ZSM -5 after calcination ZSM -5 before calcination
Absorbance
Absorbance
4
3
2
2
1
1 2000
Wavenumber (cm -1)
4000
1000
3000
2000
1000
Wavenumber (cm -1)
FIGURE 1. FTIR spectra of depolimerized zeolite (red), Bayat natural zeolite (black), sodium silicate p.a (blue) and sodium aluminate p.a (green).
FIGURE 2. FTIR spectra of synthesized ZSM-5 before (black) and after calcination (red)
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XRD analysis show that natural zeolite Bayat has Mordenite framework type [JCPDS No 29-1257] as reported by Ansori et al. [4]. The diffraction of Bayat natural zeolite being used in this work is shown in Fig. 3a they have specific diffraction pattern with 2θ at 9.93°; 22.32° and 25.96°. Figure 3b shows the XRD pattern for ZSM-5 zeolites synthesized from Bayat natural zeolite they have specific diffraction patterns with 2θ at 7.9° to 8.8° and 20.5° to 24.2˚, which is in agreement with reported diffraction pattern for ZSM-5 [10]. Figure 4 shows the simulated pattern of ZSM-5 from Bayat natural zeolite with ZSM-5 from data base of IZA online structure, they have same of specific diffraction patterns. This indicates that ZSM-5 has been succesfully synthesized. The first-order reflection of natural zeolite is observed at 2θ = 9.93°, the corresponding d spacing calculated from the Bragg’s law [5] is d = 0.89 nm. Meanwhile, for ZSM-5 zeolite shows the first-order reflection at 2θ = 7.9° and 8.8°, corresponding d spacing calculated from the Bragg’s law is d = 1.12 nm and 1.00 nm, respectively. This indicates that ZSM-5 has higher pore diameter than natural zeolite. Surface morphology and crystal size of as-synthesized zeolite after calcination are observed using SEM instrument. Figure 4b show that ZSM-5 crystals have hexagonal shape or coffin-like morphology with debris of impurities. That shape is specific character of ZSM-5 zeolite, this is similiar to the results reported by Krisnandi et al. [11]. The debris impurities may come from the natural zeolite since it was used without further purification.
(a)
(b)
FIGURE 3. XRD patterns of (a) natural zeolite and (b) ZSM-5 from natural zeolite
(a)
FIGURE 4. XRD patterns of ZSM-5 from (a) natural zeolite and (b) database of IZA structure
(b)
FIGURE 5. SEM images of (a) Bayat natural zeolite (Magnification of 500x) and (b) ZSM-5 from Bayat natural zeolite (Magnification of 7000x)
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TABLE 1. EDS Analysis of zeolite materials
Element Na Si Al Si / Al ratio
% Molar Depolimerized 1.32 0.41 0.09 4.56
a
b
Raw 0.02 1.28 0.24 5.33
c
ZSM-5z 0.02 1.62 0.09 18.0
The elemental contents of the as-synthesized ZSM-5 is determined using EDX instrument. The elemental analysis gave mass percent of Si and Al of 45.47% and 2.47%. The average Si/Al molar ratio of the synthesized zeolite determined using EDX analysis a is shown in Table 1.
CONCLUSIONS From the characterization of the as-synthesized zeolite, it is concluded that ZSM-5 zeolite has been successfully synthesized from Bayat natural zeolite. SEM image showed that zeolite ZSM-5 has hexagonal shape or coffin-like morphology with debris impurities that came from natural zeolite. Si/Al ratio was increased from 5 to 18 while Nacontent relatively similiar. ZSM-5 has larger d spacing with ZSM-5, this indicates that ZSM-5 has higher pore diameter than natural zeolite.
ACKNOWEDGMENTS Part of this work was funded by TWAS Grant No. 13-034 RG/CHE/AS_I-UNESCO FR: 3240277703 and: Hibah PUPT BOPTNNo. 1136/UN2.R12/HKP/05.00/2016.
REFERENCES 1.
R. I. Kusuma, J. P. Hadinoto, A. Ayucitra, F. E. Soetaredjo, and S. Ismadji. Appl. Clay Sci. 74, 121–126 (2013). 2. H. Liu, et al. Appl. Clay Sci. 115, 201–211 (2015). 3. M. Chareonpanich, T. Namto, P. Kongkachuichay, and J. Limtrakul. Fuel Processing Technology, 85, 1623– 1634 (2004). 4. S. Ansori, R. Sihombing, Y.K. Krisnandi. AIP Conference Proceeding 1729, 020045 (2016). 5. C. Li, Y. Ren, J. Gou, B. Liu, H. Xi. Appl. Surf. Sci. 392, 785–794 (2017). 6. J. Jiang, C. Duanmu, Y. Yang, X. Gu, J. Chen. Powder Technol. 251, 9–14 (2014). 7. Y. Yue, et al. J. Catal. 319, 200–210 (2014). 8. L. Wang, Z. Zhang, C. Yin, Z. Shan, F.S. Xiao. Microporous Mesoporous Mater. 131, 58–67 (2010). 9. M.L. Gonçalves, L.D. Dimitrov, M.H. Jordão, M. Wallau, E.A. Urquieta-González. Catal. Today. 131, 69–79 (2008) 10. M. M. J. Treacy and J. B. Higgins, MFI - ZSM-5, Calcined, In Collection of Simulated XRD Powder Patterns for Zeolites (Fifth Edition). (Elsevier, Amsterdam, 2007) p. 278. 11. Y. K. Krisnandi, et al. Procedia Chemistry. 14, 508–515 (2015).
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