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CHEMICAL PROBLEMS 2020 no. 1 (18) ISSN 2221-8688
55
UOT 541.183:543.54-414
SYNTHESIS AND PHYSICAL-CHEMICAL STUDY OF ORGANOBENTONITE-
BASED NANOCOMPOSITES
S.A. Mammadova, U.A Mammadova, D.B. Tagiyev, N.A. Zeynalov, A.I. Yagubov
Acad. M. Nagiyev Institute of Catalysis and Inorganic Chemistry National Academy of Sciences ofAzerbaijan, H.JavidAve., 113 AZ-1143, Baku, Azerbaijan e-mail: ulviyye_mammadova@mail. ru
Received 28.10.2019
Abstract: A series of experiments was conducted to obtain a nanocomposite based on organo-bentonite and a synthetic polymer polyvinylpyrrolidone by a hydrothermal method. Octadecilaminacetate-processed bentonite was used as organoclay. Obtained samples were investigated by X-ray, IR spectroscopic methods of analysis. It found that samples can also be used as adsorbents. Keywords: bentonite, polymer, hydrothermal synthesis, nanocomposite DOI: 10.32737/2221-8688-2020-1-55-60
Introduction
In recent years, the problem of lead to rise in the concentration of acid and
synthesis, studying the structure and properties of polymer nanocomposites (PNC), based on layered silicates, is - great interest to researchers as a promising direction in industry.
One of the advantages of clay minerals is that their structure allows for targeted modification to control surface properties and adsorption characteristics of natural aluminosilicates [1]. An increase in the adsorption characteristics of natural aluminosilicates is possible by ion exchange, their treatment with acids, alkalis, salts of various metals and organic compounds which
basic centers, changes in transfer energy, and facilitate electronic transitions and ion mobility [2].
The analysis of literature data showed that completely new prospects were revealed in the development of polymeric composite materials by using layered silicates as fillers with montmorillonite structure (MMT).
But, due to the fact that outer and inner surfaces of montmorillonite are hydrophilic and polar, their compatibility with the organic polymer matrix is impossible. This problem can be solved by modifying montmorillonite with organic compounds [3-7].
The use of organo-bentonite nanocomposite filler (3-5%) in the composition of polymeric materials makes it possible to regulate rheological properties of the system in a wide range which significantly improves physicomechanical properties of polymeric materials. Organoclays are better combined with polymers to form layered polymeric nanocomposites which are well dispersed in the polymer matrix [8-9].
In this regard, for the hydrothermal method of synthesis the initial reagents were taken in different molar ratios (synthetic polymer polyvinylpyrrolidone as polymer
Experiment
as a matrix
and bentonite treated and untreated with octadecylamine of acetate as organic clay, the duration of the experiments varied from 24 up to 144 hours, in the temperature range of 110-1300C, the percent of occupancy of the autoclave was 70-75%, respectively.
After the end of the experiment, the product was poured into a Petrik cup and the mother liquor was separated by decanting the next process to dry product completely. The results of hydrothermal synthesis were investigated by X-ray (XRD-based apparatus D2-Phaser "Bruker") and IR-spectroscopic
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CHEMICAL PROBLEMS 2020 no. 1 (18)
(IR- on FTIR spectroscopy Nicolefisio VSA) analysis methods.
Results and its discussion
Initially, we obtained octadecylamine constant stirring. Next, the calculated amount of acetate (ODAA) using glacial acetic acid of amine was introduced until the pH of the which was heated in a flask heater (or in a medium reached 7. The resulting solution was water bath) to a temperature of 40-500C with filtered and evaporated.
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Fig. 1. Diffraction of a) starting montmorillonite; b) montmorillonite treated with octadecylamine of acetate; c) starting polyvinylpyrrolidone; d) polyvinylpyrrolidone/organo-bentonite nanocomposite
The treatment of bentonite with octadecylamine of acetate in a solvent medium was carried out with stirring of the laundered rock of bentonite, containing 80% of MMT
Dash-Salakhly deposit of the Republic of Azerbaijan, with amine salt at a ratio of MMT: octadecylamine = 70:30 in the environment of 90% ethyl alcohol for 30 min., with the
subsequent by evaporation of excess alcohol in a water bath and drying the product to obtain a homogeneous, powdery modified organoclay. The results of X-ray analysis showed that the following phases can be distinguished in clay samples: montmorillonite, low-temperature quartz, illite, etc. (Fig. 1 a).
The main rock-forming mineral in the Dash-Salahlinsky deposit is montmorillonite. It is known that montmorillonite when heated it loses water and swells again when it enters a humid environment. As temperature rises, the mineral retains its properties to a certain limit. At high temperatures, irreversible changes in the structure of the mineral up to complete destruction are possible which adversely affects the sorption properties of clay. Therefore when using MMT, the temperature factor is taken into account. MMT has a crystalline structure with low crystallinity which is due to the content of impurities in the
composition of bentonite. After processing and purifying MMT from ODAA admixtures its crystallinity increases (Fig. 1 b).
In the figure polyvinylpyrrolidone is characterized by two diffusion reflections (Fig. 1 c), which indicates the mesomorphic nature of the mutual packing of this polymer' chains, a nanocomposite based on
polyvinylpyrrolidone and organo-bentonite (Fig. 1d) had two strongly pronounced reflex's which was due to the introduction of organo-bentonite into the composition of polymer which in turn has a crystalline structure.
Using IR spectroscopic analysis, the structures of the starting, modified of layered silicate, polymer and polymer nanocomposite were also studied. The method of IR-spectroscopy is currently one of the most common methods for identification of polymers and polymer composite materials and their structural analysis.
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Wave number (curl) Fig. 2. IR spectrum of starting montmorillonite
Wave number (cm-1)
Fig. 3. IR spectrum of montmorillonite treated with octadecylamine of acetate
According to IR spectroscopy (Fig. 2), the initial MMT of the free and associated characteristic absorption bands 2348, 3405, forms of Si - OH; the band at 1634 cm- 1 3626 cm- 1 were observed in the spectrum of refers to OH- stretching vibrations. The bands
1000-1100 and 460-500 cm- 1 are caused by vibrations of the Si - O- bond in the SiO4- -tetrahedral. Bands in the range of 3000-3400 cm-1 relate to OH- stretching vibrations of free or bound water.
On IR spectra of samples treated with organic compounds, these bands are absent (Fig. 3). This is due to the fact that the molecules of organic compounds are
5 5 3 ft 3 S 3
s
In contrast to natural bentonite, in the IR spectrum of organo-bentonite there is an increase in the absorption bands in the region of 2672-3254 cm-1 and 1555-1620 cm-1, associated with asymmetric stretching and deformation vibrations, which form a covalent bond with aprotic centers of the surfaces of aluminosilicate sorbents by the donor-acceptor mechanism. The absorption bands of 2800-
distributed in the into interlayer space and displaced the water from there. The absorption bands in the regions of 1555-1620 cm-1 and 1868 cm-1 characterize the vibrations of the C - H bond, which indicates the presence of organic compounds in the structure. The absorption bands 3189-3253 cm-1, 1875 cm-1, appearing in the IR spectrum, belong to the amino groups and acid residues.
3000 cm-1 belong to the asymmetric and symmetric valence vibrations of the CH2 group of the adsorbed surfactant.
An important role in the analysis of polymers is played by structurally sensitive bands in the IR spectra, which are excellent importance in establishing the "structure-property" relationship.
Fig. 4. IR spectrum of the starting polyvinylpyrrolidone
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Wave number (cm-1 )
Fig. 5. IR spectrum of polyvinylpyrrolidone/organo-bentonite nanocomposite
Comparing the IR spectra of the initial to reveal appearance of new absorption bands. polymer (Fig. 4) with the IR spectrum of the It can be seen that the IR spectrum of the obtained composite (Fig. 5) makes it possible studied polymer systems contains several
characteristic bands; these are stretching vibrations of the OH group in the range O-H = 3400-3415 cm-1 and stretching vibrations of the aliphatic CH group 2041, 2955 cm-1.
Thus, on the basis of the studies, the optimal condition for obtaining a nanocomposite at a temperature of 1250C and a holding time of 72 hours was found. In the course of the research, the experimentally obtained (organoclay, nanocomposite) samples were studied by physicochemical methods. Also, explorations were conducted to study sorption properties of the obtained
nanocomposite. The study into sorption properties of the obtained product was carried out under static conditions using model aqueous solutions of metal salts such as lead, molybdenum, tungsten with a concentration of 1 g/l. Results obtained made it possible to establish that nanocomposites based on polymer and organo-bentonite can be used in the process of heavy metal ion extraction from model aqueous solutions (in this case, from wastewater). More details of the studies will be reported in future work.
References
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2. Mamedova S.A., Heydarzade G.M., Yagubov A.I., Nuriev A.N., Osmanova U.G., Ismaylova V.A. Method of obtaining organoclay. Eurasian patent 028314.
3. Shao H. et al. Preparation of Clay Nanocomposites Matrix. Chemical Science and Technology. 2013, vol. 2, no. 3, pp. 128- 134.
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6. Sirait M. and Nurdin B., Siregar N. Preparation and Characterization of Natural Bentonite in to Nanoparticles by Co-precipitation Method. The 6th International Conference on Theoretical and Applied Physics (The 6th ICTAP). American Institute of Physics. 2017, 1801, (020006).
7. Ilyicheva E.S., Gotlib E.M. Nanocomposites based on rubbers and layered silicates. Herald of Kazan Technical University. 2011, no. 18, pp. 105-110.
8. Mamedova S.A., Yagubov A.I., Fatullaeva T.A. Medzhidova A.A., Abasov M.G. Production and IR-spectroscopic studies based on modified bentonites. News of the VSTU. The series "Chemistry and technology of organo-organic monomers and polymeric materials". 2018, no. 4 (214), pp. 135-140.
9. Chvalun S.N. Polymer nanocomposites. Nature. 2000, no. 7, pp. 22-26.
ÜZViBENTONÍT dSASINDA NANOKOMPOZiTLdRÍNSÍNTEZÍ Vd FÍZÍKÍ-KÍMYdVI
todqíqí
S.A. Mzmmzdova, Ü. O. Mzmmzdova, D.B. Tagiyev, N.A. Zeynalov, B.L Yaqubov
AMEA-nin akademik M. Nagiyev adina Kataliz vd Qeyri-üzvi Kimya institutu, AZ-1143, Azdrbaycan, Baki, H.Cavidpr., 113; e-mail: ulviyye_mammadova@mail.ru
Hidrotermal üsulla üzvi gil vd sintetik polimer polivinilpirrolidon dsasli nanokompozitin alinmasi istiqamdtindd bir sira tdcrübdldr aparilmi^dir. Üzvi gil kimi oktadesilaminasetatla i§ldnmi§ bentonit istifadd edilmi^dir. Alinan nümundldr rentgenoqrafik vd iQ spektroskopik analiz üsullari ild tddqiq edilmi^dir. Müdyydn edilmi^dir, ki nümundldr hdm dd adsorbent kimi istifadd edild bildlldr. Agar sozlsr: bentonit, polimer, hidrotermal sintez, nanokompozit.
СИНТЕЗ И ФИЗИКО-ХИМИЧЕСКОЕ ИССЛЕДОВАНИЕ НАНОКОМПОЗИТОВ НА ОСНОВЕ
ОРГАНОБЕНТОНИТА
С.А. Мамедова, У.А. Мамедова, Д.Б. Тагиев, Н.А. Зейналов, А.И. Якубов
Институт Катализа и Неорганической Химии им. академика М.Нагиева AZ-1143, Азербайджан, Баку, пр. Г.Джавида, 113 e-mail: ulviyye_mammadova@mail.ru; Fax: (+994 12) 5108593
Была проведена серия экспериментов по получению нанокомпозита на основе органоглины и синтетического полимера поливинилпирролидона гидротермальным способом. В качестве органоглины был использован бентонит, обработанный октадециламинацетатом. Полученные образцы исследовали методами рентгеновского и ИК-спектроскопического анализа. Было установлено, что образцы также могут быть использованы в качестве адсорбентов. Ключевые слова: бентонит, полимер, гидротермальный синтез, нанокомпозит.
