SYNTHESIS OF HIGH-SILICONE ZEOLITES

. During the study, the synthesis, texture and physicochemical characteristics of high-silica zeolites from bentonite and kaolin were studied. Adsorption isotherms are characteristic of type IV according to the de Boer classification and characterize the adsorption of monocellular substances. On the isotherm in the range P/P 0 = 0-0,05, monomolecular adsorption in mesopores and adsorption in micropores are observed. At P/P 0 = 0,05, mono-and polymolecular adsorption is observed in mesocytes. P/P 0 = 0,05-0,4 is a polymolecular adsorption field. Based on the obtained results, adsorption of gases CO 2 , H 2 S and NO 2 by absorption of a mixture of salts CaCl2 • ZnCl2 • MnCl2/ HSZ into a synthesized sorbent was investigated. According to the results of the experiments, the dynamic capacity CaCl 2 •ZnCl 2 • MnCl 2 / HSZ for hydrogen sulfide was 2.76% by weight. The total dynamic capacity of the adsorbent by H 2 S was higher than 20-25%.


Introduction.
In recent years, natural and artificial zeolites have been widely used in hydrocarbon processing. Adsorption methods are one of the most common hydrocarbon purification methods in the industry. Their use allows returning to production several valuable compounds [1][2]. The study of zeolites is devoted to many works. Zeolites are a microporous substance with the correct crystal structure and a controlled size not exceeding 2 nm [3][4][5][6]. Zeolitic scaffolds are lattices consisting of tetrahedral T-atoms (Т = Si, Al, etc.), Connected by atoms in oxygen. More than 200 types of synthetic zeolites of various structural types are currently known [7][8][9]. However, no more than 10% of all known structures are produced in industry, and only 5 structural types are actually used as catalysts [10][11][12][13]. The most important requirements for adsorbent materials are high specific surface area, selectivity and ease of regeneration [14][15]. The adsorbent must also be inexpensive and harmless, non-corrosive, capable of maintaining its adsorption properties for a long time and having high mechanical strength. One of the most common adsorbents is activated carbon, which is available in various brands. One of the most important directions today is the development of environmentally friendly sorbents, preservatives and catalysts based on local raw materials [16][17].
Experiment. To determine the chemical and physicochemical characteristics of the synthesized high-silicon zeolites, samples of pellets weighing 100 g were placed in a glass flask with a volume of 250 cm 3 and poured with 150 cm 3 of distilled water. The flask was stirred on an АВУ-6 device at 120 rpm for 24 hours. After drying, the adsorbent was passed through a 0.5 and 0.25 mm sieve and the remaining samples through a 0.25 mm sieve were passed through a 0.5 mm sieve. chemical characteristics were studied. Before acid treatment, the soil was ground to 0.08 mm. To 10 g of ground, the soil was added 40 g of heated H2SO4 and heated by stirring in a water bath. After treatment, the soil was filtered through a paper filter in a Buchner funnel and washed with distilled water at pH = 5.4-5.7. The soil was then dried in an oven at 120 0 C with filter paper for 5 hours. The distribution of pores by specific surface area and size was detected on the automatic absorptiometer "ASAB 2010" by low-temperature nitrogen desorption. Sedimentation analysis was carried out by the "Oden method" in water and an aqueous glycerol mixture in various dispersion media. X-ray phase analysis (Co-Ka irradiation) was performed on a DRON-4 diffractometer with a cobalt X-ray tube. The PDF-2 database of the International Diffraction Data Centre (JCPDS, 1999) was used for the analysis of diffractograms. The parameters of the porous structure of the samples were determined by lowtemperature nitrogen desorption in a Quanchrome NOVA analyzer (USA). Before measurement, each sample was degassed under vacuum at 250 0 C for 2 hours. The subjects of the study were bentonite Navbahor and kaolin Pakhtachi [19][20].
The synthesis of high-silicon zeolite (HSZ) was carried out as follows: by mixing 30 g of bentonite in 300 ml of bi-distilled water, a suspension was prepared and slowly mixed, during which the bentonite-containing minerals were separated into fractions. The resulting suspension was left for a day. The sample was then centrifuged at 7,000 rpm for 5 minutes. The resulting fraction was dried in the open air at room temperature for 6 hours and then at 65 0 C for 12 hours. The sample was then activated in 1.5 M nitric acid at 80-90 0 C for 2 hours. After activation, 200 ml of distilled water was added to the bentonite suspension and cooled rapidly.
The resulting sample was then washed several times with distilled water, centrifuged and dried at room temperature for 12 hours and then at 65 0 C for 12 hours. Chemically treated with sodium carbonate and 25% nitric acid in the same order.
Results and discussion. In order to purify the oil products of the various gases, 20% of the solutions CaCl2, ZnCl2, MnCl2 were swallowed for 2 hours on the highsilica zeolite obtained by the above method under strong shaking. The result was a sample containing CaCl2•ZnCl2•MnCl2/HSZ. The chemical composition of the sample was analyzed by an energy dispersion spectrometer and a radiographic method using a scanning electron microscope. . Figure 2 shows the differential curves of adsorption-desorption isotherms and pore distribution radius of the synthesized HSZ. Adsorption isotherms are characteristic of type IV according to the de Boer classification and characterize the adsorption of meso-cellular substances. On the isotherm in the range P/P0 = 0-0,05, monomolecular adsorption in mesopores and adsorption in micropores are observed. At P/P0 = 0,05, mono-and polymolecular adsorption is observed in mesocytes. The P/P0 = 0,05-0,4 field is polymolecular adsorption which is used in the BET equation to determine the specific surface area (Ssol). On the isotherm of adsorption, P/ P0 = 0.4-1.0 characterizes the occurrence of capillary condensation in mesocytes.

Fig.2. Differential curves of isotherms of adsorption-desorption and pore distribution radius of synthesized sorbents
Thus, some textural and physicochemical characteristics of a high-silica zeolite obtained from bentonite and kaolin have been studied.