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a b c
Figure 1-Schematic picture of interaction of polyacrylic acid (a) molecules (n=2) (b)on the solid oxide surface (c)
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Khayitov Ruslan Rustamjonovich, Institute of General and Inorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan, doctoral student, the Laboratory of Chemistry of Oil
E-mail: leo-bexa@mail.ru Narmetova Gulnara Rozukulovna, Institute of General and Inorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan, Chief scientific officer, the Laboratory of Chemistry of Oil
Production of activated coal from the pits of apricots and peach for the adsorption purification of the waste Diethanolamine
Abstract: The obtained activated carbons from pits of apricot and peach. Conducted carbonization of the raw material in the temperature range 600-900 °C in a quartz reactor placed in an electric furnace with controlled heating. The resulting activated carbons with water vapor for 1-5 hours. Determined sorption and physical characteristics of the obtained activated carbons were compared with other known sorbents.
Keywords: activated carbon, apricot pits, peach pits, carbon AG-3, activate, carbonizate, alkanolamine, regeneration.
Introduction. The production of activated carbon (AC) has been steadily increasing and their application is continuously expanding. The traditional raw material for the production of AU are wood, peat, peat coke, some coals and polyoxy based on them. In Uzbekistan, despite the large demand for AU, they do not produce. In addition, food enterprises of the Republic annually produce large amount of waste of processing of fruits of apricots and peaches, is widely cultivated on the territory of the Republic. According to available information [1] named waste can serve as a good raw material for the production of AC. There is sufficient information about the kernel processing polyethylene into valuable products [2], but literature data on receipt and use of coal sorbents based on shell pits are scarce [2-4].
AC have a well-developed porous structure and large specific surface area (up to 1000 m 2/g). Carbon adsorbents are used primarily for drying, purification and separation of gases, purification of natural and waste waters in the process of extracting precious metals, decontamination of contaminated fluids, for separation of harmful impurities in the atmosphere in small concentrations, as catalysts and even for the analysis of complex mixtures that differ only in isotopic composition.
In the world practice for cleaning saturated solutions of alkanolamines on the units amine treatment of natural gas from acid components is widely used activated coal brand AG-3. Activated coal brand AG-3 is obtained in the form of granules from coal dust and binder method of treatment with water vapor at a temperature of 850950 °C.
Uzbekistan has three major gas processing complex Mubarek gas processing factory (mgpf), the washing installation of the enterprise "Shurtanneftgaz" and Shurtan gas and chemical complex. The units amine treatment of natural gas from acidic components higher the number of plants for the purification of saturated alkanolamines used activated coal AG-3.
We must remember that activated coal AG-3 is of foreign origin and imported for currency.
In the present work, the aim was — obtaining activated carbon from local raw materials for the regeneration of alkanolamines in the process amine treatment of natural gas instead of sorbent AG-3.
Objects and methods of research. The object of
research was the benchmark of aromatic hydrocarbons (benzene), methylene blue (MB), iodine, water vapor, carbon adsorbents (coconut shells, the shell cedar nut, shell almonds, activated coal brand AG-3), as well as the proposed coal — local activated carbon on the basis of fruit pits (apricot and peach).
In the course of the research were studied the carbonization of the raw material in the temperature range 600-900 °C in a quartz reactor placed in an electric furnace with controlled heating. The temperature in the furnace was controlled using a thermocouple and potentiometer. Processing was subjected to a fraction of 0,2-5,0 mm and dried at 110 °C to constant weight. Released gaseous products ofpyrolysis is evacuated from the reactor via the vapor tube and directed into a cooled condenser for condensation of water vapor and tar. To achieve the required temperature of the experiment, the samples were kept in the reactor for 0,5-3,0 hours, and then cooled to room temperature. Chilled carbonizate unloaded from the reactor by standard methods was determined by their absorption properties [3-5]. The activation process of carbonisation studied in the same reactor. This carbon matrix obtained by the pyrolysis of raw materials was charged into the cold reactor, which is purged with a current of nitrogen gas for 15 min to remove oxygen from the reaction zone [6-8]. Then we carried out heating the samples to a final temperature of activation, which was in the range of 600-900 °C.
Upon reaching the desired temperature in the reactor was fed water vapor from the generator within 1-5 h. After heat treatment activity left to cool to room temperature.
The quality of the desired products was monitored by measuring their adsorption activity for methylene blue (MB), iodine, benzene, water vapor [9-11], while it was evaluated their total porosity by boiling in water [12; 13].
Analysis of apricot and peach kernels is established that the mass fraction in them the shell is 85-90, its moisture content is in the range of 20-21, and ash content — 0,27-0,3%. The obtained experimental results are shown in tables 1 and 2, allowed us to note that the optimal conditions of carbonization of the bones to peaches are a duration of 1 h at 750 °C; apricots for 2 h at 600 °C.
Results and their discussion. Upon receipt of the activated carbon from the seeds of apricots and peach obtained the following results (tab. 1 and 2).
Table 1. - The conditions and results of carbonization of apricot pits fragments
Process t - the speed The mass of The mass of h2 o,% V Adsorption activity
temperature, of tempera- raw mate- carbonizate, condensate, for for water va-
°C ture rise, min. rial, g. g. ml. g/100g* por, cm 3/g
600 0-90 8,4 2,14 24,86 5,5 1,26 0,6577
650 0-90 10 2,5 24,9 6,5 0,93 0,0268
750 0-90 10,8 2,54 23,52 7,8 0,62 0,1734
850 0-90 10,27 3,72 36 8,7 0,34 0,1233
900 0-90 11,16 2,78 22,4 9 0,09 0,1088
* - capacity determined in dynamic conditions in the liquid phase
Table 2. - The conditions and results of carbonization of peach pits fragments
Process t - the speed The mass of The mass of h2 o,% V Adsorption activity
temperature, of tempera- raw mate- carbonizate, condensate, for for water va-
°C ture rise, min. rial, g. g. ml. g/100g* por, cm 3/g
600 0-90 5,06 0,26 5,14 5,2 0,52 0,2286
650 0-90 5,27 2 38 6,1 0,87 0,2997
750 0-90 5,29 1,54 29,1 8 1,18 0,3383
850 0-90 5,39 1,67 31 8,6 0,46 0,2466
900 0-90 5,36 1,47 27,4 8,9 0,24 0,1966
* - capacity determined in dynamic conditions in the liquid phase
The resulting carbonizate stone raw material is activated. The conditions and results ofactivation are shown in tables 3-5. Table 3. - The activation conditions of carbonizate of apricot
T, °C The time of exposure, min. The degree of burning, % Adsorption activity
for MB, m2/g for I2,%
800 60 28,82 5,18 21,7
850 120 27,10 6,39 25,34
Table 4. - The activation conditions of carbonizate of peach
T, °C The time of exposure, min. The degree of burning, % Adsorption activity
for MB, m 2/g for I2,%
800 60 16,39 4,19 8,52
850 120 15,89 5,38 12,34
Based on the obtained data (tab. 3,4), it was stated that Compared some of the characteristics of the ob-
the optimal conditions for the activation of carbonizate tained activated carbons from stone raw materials with stone raw material temperature of 850 °C, duration 2 h. other well-known commercial activated carbons (tab. 5).
Table 5. - Some of the characteristics of the carbon adsorbents
Mark of adsorbent Adsorption activity Specific surface, m 2/g Source of information
for MB, m 2/g for I2, % for C H , 6 6 g/100g
Shell apricot walnut* 6,39 5,34 1,26 800-890 Results of their own experiments
Shell peach walnut* 5,38 12,34 1,18 878-936 Results of their own experiments
Coconut shells > 2,5 11,0 1,05 ~500 PJ, Philippines, Japan
The shell cedar nut 3,18 14,0 0,73 ~ 250 Russia, Siberia, Tomsk
Shell almonds 6,3 9,0 1,10 650-700 Central Asia, Kazakhstan, Astana
Activated coal brand AG-3 - - 1,23 480-500 Russia, Rostov-on-Don
* We received samples of stone active carbon
Conclusion. Comparison with literature data demonstrate the feasibility ofprocessing described waste
revealed that the obtained target products for adsorption of the Republic of Uzbekistan on carbon adsorbents. activity are at the level of the activated carbon from Evaluated the prospect of processing the waste pits
stone raw materials, which is one of the highest quality of apricots and peaches are formed on the enterprises of
global industrial activated coals, and far superior to many food industry of the Republic of Uzbekistan on activated
other carbon adsorbents (table 5). Thus, the studies carbons.
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Sobirov Mukhtorjon Mahammadjanovich, Junior scientific researcher Academy of Sciences Republic of Uzbekistan Institute of General and inorganic chemistry, Tashkent, Uzbekistan E-mail: fcb_m_2011@mail.ru Sultonov Bokhodir Elbekovich, PhD in technique, senior reseacher of laboratory of Phosphorous fertilizers, Academy of Sciences of the Republic of Uzbekistan, Institute of General
and inorganic chemistry, Tashkent, Uzbekistan E-mail: i_umbarov@mail.ru Tajiev Sayfuddin Muhitdinovich, PhD in chemistry, Head of laboratory of Complex fertilizers, Academy of Sciences Republic of Uzbekistan Institute of General and inorganic chemistry, Tashkent, Uzbekistan
E-mail: sayf49@rambler.ru
Suspended sulfur containing fertilizers based on low-grade Kyzyl-kum phosphorites
Abstract: In this article, the principal opportunities for intensive technology of complex suspended sulfur-containing fertilizers wide actions based on unconcentrated phosphorites from Central Kyzylkum
