Received 9 November 2015; accepted 15 January 2016; published 18 January 2016
The modern scientific and technological progress resulted in the rapid growth of industry and agriculture is accompanied by involvement in economic circulation of non-traditional types of mineral raw materials, one of which is zeolites   .
It is no secret that the specific crystal structure of zeolite determines the number of very valuable properties, such as thermal stability, adsorption, catalytic activity, acidity, cations exchange and molecular sieves; zeolites have important applications in refining processes at the petrochemical industry, as well as gas separation, water purification at mining industry and environmental catalysis  .
Obtaining of zeolites for drying natural gas, purification of gas and liquid industrial waste from environmentally harmful components, increasing the productivity of a number of branches of agriculture (animal husbandry, aviculture, crop and so on) is particularly important. The rapidly growing demand for zeolites necessitated their production  - .
Most zeolites are synthesized from commercial (Martucci et al., 2009; Tanaka et al., 2009; Trejda et al., 2010; Morales-Pacheco, 2011; Xue et al., 2012) and natural raw (fly ash, kaolin, bentonite and others) (Moriyama et al., 2005; Terzano et al., 2005; Tanaka et al., 2008; Walek et al., 2008; Font et al., 2009; Kumar et al., 2009; Ríos et al., 2009; Goni et al., 2010; Ahmaruzzaman, 2010) materials. Many of them have been synthesized, at a given temperature and crystallization time, from gels containing Na2O-Al2O3-SiO2-H2O. Some sources of silicon are: Na-silicate HS-40 (Sig and Seung, 2004, Chen et al., 2009), Na-silicate, Cab-O-Sil M-5 fused silica (Rivallan et al., 2010), fumed silica (Xu et al., 2010), UltraSil silica TMA-SiO2 and Cab-O-Sil TMA-SiO2 (Shvets et al., 2008). On the other hand, some of the sources of aluminum that have been employed are: Na-aluminate (Anuwattana and Khummongkol, 2009, Gupta et al., 2009) and Al-isopropylate (Tosheva et al., 2005). Surfac- tants of different chain lengths have been used as templates. Among them, the following can be mentioned: C16H33(CH3)3N-OH/Cl, C12H25(CH3)3 N-OH/Cl, C14H29(CH3)3N-Br, C16TMA-OH and C8TMA-Br (Han et al., 2009, Sakthivel et al., 2009). The use of such synthetic and natural materials leads to the synthesis of such zeolites as the chabazite, phillipsite, analcime.
The aim of the present work is the synthesis of zeolite mordenite based on natural raw materials and structure- forming component tetraetilamonium iodide (TEAI).
In addition it should be noted that the synthesis of the zeolite mordenite is carried out using local raw materials, what leads to a reduction cost price desired product.
This fact motivated us to evaluate the possibility of investigating the reactivity of ash as a raw material in the formation of zeolites and or zeolitic materials   .
This article is devoted to the study of the process of preparing a zeolite with an organic component tetraetilamonium iodide (TEAI). The study of zeolitization process in the systems with participation organic component is particularly interesting, because it affects the structure and properties of zeolites (thermal stability, adsorption and catalytic properties). From literature data it is known that if the synthesis is carried out in the presence of large cations such as TEA, then crystallizing the composition of the zeolites become more high silica than normal samples  .
Also during the synthesis volcanic ash was used from the deposit by named Dzheyranchel of Azerbaijan Republic.
Based on the above synthesis of zeolites based on natural raw materials presents both scientific and practical interest.
The volcanic ash sample was dried at room temperature, ground and the grain size employed in the synthesis was less than 200 mesh. With the aim of converting the volcanic ash into zeolite or zeolitic materials, several experiments were done. The experiments (Table 3) were carried out in Parr steel autoclave reactor in static conditions under hydrothermal conditions, autogenic pressure, temperature of 220˚C, with high and low concentrations of TEAI and reaction time from 48 to 192 h. Once the run was completed and the system cooled down, the products were washed off with abundant distilled water and dried at 120˚C for 15 h. The calcinations of samples prepared with template agent were carried out in air at 600˚C for 6 h.
Natural raw material and products from this hydrothermal treatment were identified by the rentgenophase analysis methods (RFA) on the apparatus of BRUKER D2 PHASER and weight-spectroscopic analysis method on the apparatus of ICP-MS Agilent 7700 and X-ray analysis methods (RSA). Of the zeolitic material the Na-mordenit zeolite was found to be the most effective for the retention of cations Pb2+, Zn2+, and Ba2+.
3. Results and Discussion
The chemical composition of the ash was determined by X-ray fluorescence (XRF; Table 1), and it was used to carry out the experiments. The volcanic ash (molar ratio SiO2/Al2O3 = 9.2) was collected at the bottom of the Jeyranchol volcano. Minerals found correspond mainly to kаоlinite Al2(OH4)(Si2O5) (7.17x, 1.499, 3.588) and clayey mineral montmorillonite Al2(OH)2∙(Si4O10)∙ mH2O (9.5 - 20x, 4.488, 2.558) followed by minor amounts of quartz SiO2 (3.34х, 4.222, 1.811); cakhcholonq SiO2 (4.05х, 2.4949, 1.6118); carbonate CaCO3 (3.03x, 1.873, 3.853); feldspar Ca(Al2Si2O8) (3.20x, 2.5096, 2.1356); gypsum CaSO4∙2H2O (4.29x, 2.877, 3.066); cordierite (Mg,Fe)2Al3(AlSi5O18) (3.00x, 3.349, 8.298) and others which probably come from the volcanic ash (Table 2).
The reaction product is the result of a chemical reaction between the volcanic ash, NaOH 0.5 M solution at 220˚C temperature reaction whether in presence of TEAI, respectively. Mordenit-like zeolite crystallized at 144 h of reaction time.
Table 1. Major elements composition of the volcanic ash.
Table 2. The diffractometeric dates of the volcanic ash.
the percentage content of these foods varies depending on synthesis conditions. But the order of present study was to obtain mordenite zeolite, so further research has gone into the synthesis of pure zeolite mordenite. At the beginning of crystallization (0 hour) crystallinity degree of the sample taken from solid phase of RM is equal to 10 wt%. This value corresponds to the amount of preliminarily introduced in RM crystal seed. Dependence of change of static adsorption capacity from duration of crystallization of volcanic ash in sodium silicate solution shows that after 144 hours of crystallization mordenite type zeolite achieves maximum (for this type zeolite) adsorption capacity. This value corresponds to 100% crystallinity degree of zeolite and it is confirmed with RFA data (Figure 2).
In Table 4, it has been shown the diffractometric datas of the synthesized zeolite mordenite.
After identification of the obtained pure zeolite mordenite by RSA method has been found that the silicate modulus of zeolite is SiO2/Al2O3 = α = 10.
Table 3. Experimental conditions and reaction products related to the chemical reaction between the volcanic ash with low and high TEAI concentrations and a 0.5 M NaOH solution.
Table 4. The diffractometeric dates of the zeolite mordenit.
Figure 1. Diffraction patterns of samples obtained during crystallization of volcanic ash-NaOH-TEAI: 1) mordenite; 2) mordenite-analsime; 3) analsime; 4) analsime-quartz.
Figure 2. Diffraction patterns of mordenite samples obtained during crystallization of volcanic ash in sodium silicate solution in presence of organic components for: (a) 2 hours; (b) 4 hours; (c) 6 hours.
Thus, increase of the crystallization speed of mordenite type zeolite from volcanic ash (compared with known methods) is achieved due to high alkalinity of RM and introduction of crystal seed. Implementation of the developed method allows extending the raw materials base, simplifying the synthesis and reducing the cost of powdery mordenite type zeolite.