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Date submitted2024-05-06
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Date accepted2024-06-14
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Date published2024-07-04
Natural carbon matrices based on brown coal, humic acids and humine extracted from it for purification of aqueous solutions from low molecular weight organic impurities
Heterogeneous systems including natural carbon matrices in the solid phase and aqueous solutions of low molecular weight organic compounds with positive and negative variations from ideality in the liquid phase are considered. The technical characterization of the considered supramolecular ensembles on the basis of brown coal of the Kara-Keche deposit (Kyrgyzstan), humic acids and humine extracted from it is given. Functional analysis of the samples was carried out using FTIR spectroscopy. The morphology of the surface of the considered carbon matrices has been investigated, in different points of which the local microelement composition has been established. An X-ray phase analysis of Kara-Keche brown coal and humic acids and humine extracted from it was carried out. The isothermal adsorption of bipolar molecules of glycine and urea, neutral D-glucose from aqueous solutions on solid carbon sorbents has been studied. An assumption has been made about the adsorption of low molecular weight organic compounds from aqueous solutions on humine and Kara-Keche coal in irregularities and pores of the carbon matrix of sorbents, for humic acids – on surface reaction centers. Due to its developed pore structure and resistance to acids and alkalis, humine from Kara-Keche coal is recommended for the purification of industrial wastewater from low molecular weight organic ecotoxicants.
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Date submitted2024-04-22
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Date accepted2024-06-13
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Date published2024-07-04
Lithification of leachate from municipal solid waste landfills with blast furnace slag
- Authors:
- Mariya A. Pashkevich
- Yuliya A. Kulikova
The article presents an alternative method of utilization of blast furnace slag and leachate from solid municipal waste landfills, the formation of which occurs during the infiltration of atmospheric precipitation through the thickness of deposited waste. The method is based on the conversion of leachate from the liquid phase to the solid aggregate state by lithification using blast furnace slag as an astringent material. The hydraulic activity of slag, which depends on the amount of oxides contained in it, has been estimated. The investigated slag belongs to the 3rd grade, which confirms the possibility of its use as an astringent material. The filtrate was analyzed for the content of various elements, and the maximum permissible concentrations for each element were found to be exceeded. Chemical and biological oxygen demand were determined, and critically high values were installed (17200 mgO2/l and 4750 mgO2/l, respectively). The lithification process was divided into two stages. The first stage was to reduce the organic component in the filtrate using a coagulant, aluminum sulfate; the second stage was slag hydration. The optimum ratio of lithificate components in terms of mixture solidification rate was established at 1:0.03:1.25 (leachate, coagulant, blast furnace slag). The obtained material was analyzed for the solubility and content of various forms of metal. It is established that at infiltration of atmospheric precipitations through lithificate only 3 % of material will be washed out; concentrations of gross and mobile forms of heavy metals do not exceed the maximum permissible, except for the gross content of arsenic, mobile, and water-soluble forms of which were not found. The values of chemical (687 mgO2/l) and biological (173 mgO2/l) oxygen demand in the aqueous extract from lithificate decreased more than 25 times in comparison with the initial filtrate. According to the results of toxicological studies, lithificate was assigned an IV class of waste hazard, which confirms the possibility of its use as bulk material at landfills.
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Date submitted2022-11-11
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Date accepted2023-01-19
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Date published2023-12-25
Evaluation of the efficiency of sorbents for accidental oil spill response in the Arctic waters
The development and operation of new oil fields on the Arctic shelf increases the risks of oil spills, which require the use of oil spill response tools and materials that are efficient in harsh climatic conditions. The question of actual efficiency of sorbents for reducing the level of oil pollution in the conditions of the Arctic and subarctic waters is relevant. The work is aimed at a comparative study of the efficiency of sorbents of mineral and organic origin used by coastal enterprises in the Kola Bay as well as a sorbent based on chitin in model systems simulating real conditions in sea waters. The characteristics of sorption agents were determined applying ASTM F716-18 procedure. Sorption capacity was evaluated in respect of ARCO grade oil, diesel fuel and marine oil. The efficiency of sorbents was estimated in model systems “sea water – oil” at water temperature corresponding to the average annual surface temperature in the Barents Sea. Actual data on sorption capacity of commercial sorbents “Lessorb”, “Novosorb”, a sorbent based on vermiculite and chitin sorbent in relation to potential pollutants of waters were obtained. The dynamics of sea water saturation with oil products at –0.5 (±1) and 10 (±1) °С was determined. It is shown that at higher temperature the concentration of oil products in sea water column (in the presence of an oil film on the surface) is on average four times higher than at low temperature. Kinetic dependences were obtained that describe the content of oil products in water column and near-surface layer of sea water in the presence of the studied sorbents at 5 (±1) °C, corresponding to the average annual temperature in the Kola Bay of the Barents Sea. A method is proposed for evaluating the efficiency of sorbents from the values of regression coefficients characterizing the dependence of oil products content in sea water on the character of sorbent and duration of its action.
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Date submitted2019-01-16
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Date accepted2019-03-07
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Date published2019-06-25
Sintered sorbent utilization for H2S removal from industrial flue gas in the process of smelter slag granulation
- Authors:
- A. B. Lebedev
- V. A. Utkov
- A. A. Khalifa
Authors suggest removing hydrogen sulfide from the hot industrial gas at temperatures 200-300 °C and its subsequent interaction with Fe 2 O 3 . For this purpose the following sorbents have been proposed: a mixture of iron oxide and fly ash; iron oxide and pumice; different samples of red mud (bauxite treatment residues containing iron oxide). To prevent dusting and loss of absorbing capacity, the sorbents were shaped into porous granules with other metallic oxides. Materials utilized in the study were obtained the following way: mixing of Fe 2 O 3 with fly ash; sintering of the mixture with red mud. The blend contains aluminum oxide and silica, which can act as matrix shapers, alkali oxides and fluxing agents that reduce the temperature during metal sintering. After the samples had been saturated with sulfur, they were positioned in a venting reservoir, where under the temperature 600-700 °C desorption to the initial state occurred by means of passing an air flow through the sorbent layer. In the process of this operation, sulfur dioxide was released and reactive metal oxides re-emerged. Desorption also generated a small amount of elemental sulfur and sulfuric acid. Absorbing capacity was assessed at higher temperatures, efficiency of H 2 S removal reached 95-99.9 %. Proposed technology of air cleaning is recommended to use in metallurgic processes with elevated atmospheric pollution, e.g. granulation of melted blast-furnace slag.
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Date submitted2016-10-27
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Date accepted2017-01-02
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Date published2017-04-14
Chemistry as a basis for solving environmental issues
- Authors:
- V. E. Kogan
- T. S. Shakhparonova
The article summarizes over 40 years of authors’ experience in the field of physical chemistry and chemical technology of glassy state of materials. It is shown that environmental issues are caused not by Chemistry as a science but by actions of ecologically illiterate humans using its advances. It is noted that without chemistry humankind cannot live comfortably and solve existing environmental problems. In support these facts we describe several developments made by authors of this article in energy industry, high temperature machinery, glass production technology, glassy phosphate fertilizers, production of non-waste systems and complex research of physical-chemical principles of glassy oil sorbents production of organic and non-organic nature.
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Date submitted2015-10-07
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Date accepted2015-12-27
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Date published2016-08-22
Phase transformations in synthesis technologies and sorption properties of zeolites from coal fly ash
- Authors:
- O. B. Kotova
- I. L. Shabalin
- E. L. Kotova
Coal fly ash is generated in the course of combustion of coal at thermal power plants. Environmental problems increase sharply without disposing that industrial waste. Technologies were tested of hydrothermal synthesis of zeolites from fly ash forming during combustion of coal at thermal power plants of the Pechora coal basin and dependences were identified of the experiment conditions on physical and chemical properties of the end product. It is demonstrated that synthesizing zeolites from fly ash is the first stage of forming ceramic materials (ceramic membranes), which defines the fundamental character (importance) of that area of studies. It was for the first time that sorption and structural characteristics and cation-exchange properties of fly ash from the Pechora basin coals were studied with respect to, Ba 2+ and Sr 2+ .
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Date submitted2015-08-20
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Date accepted2015-10-17
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Date published2016-04-22
Increasing the accuracy of the fast laser measurments transparent solid and liquid films thicknesses
- Authors:
- A. B. Fedortsov
Nondestructive optical methods for measuring of the «thick» films thickness of the order of 0,001-1,00 mm are analyzed. It is shown that using the laser beam radiation and modern optical and electronic schemes possible to decrease the time of single measurement to 1ms and less at the measuring frequency of 10-50 Hz. The possibility of measuring thickness and spreading coefficient and evaporation kinetics of liquid films is demonstrated. A new computer method of the data processing aimed to determine the film thickness from the angle dependence of the laser beam reflection coefficient by the film is offered. The offered procedure and the experimental technique realizing it permits to decrease the thickness determination uncertainty to the order of ten.
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Date submitted2015-08-09
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Date accepted2015-10-05
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Date published2016-04-22
Inorganic and organic vitreous foam materials and prospect of environmental cleaning from oil and oil products pollutions
- Authors:
- V. E. Kogan
The analysis of own experimental materials which are part of the new scientific direction – complex research of physical and chemical regularities of novel inorganic and organic vitreous sorbents and investigation of the oil and oil products absorption processes by that sorbents developed on department of the General and Physical Chemistry of National Mineral Resources University (Mining University) under the leadership of the author of this paper is provided. In particular, specifics of kinetic curves of oil absorption for sorbents with a vitreous surface are experimentally established and theoretically proved by the conducted researches.
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Date submitted2009-09-21
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Date accepted2009-11-10
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Date published2010-06-25
Simultaneous doping of silicon carbide with aluminum and nitrogen
- Authors:
- I. I. Parfenova
Three atomic shell cluster of SiC is treated as a set of chemical bonds with tetrahedral coordination. Chemical bonds energies are determined in tight binding approximation taking into account second neighbors interaction and relaxation of atomic positions. Correlations in behavior of Al and N atoms in Si-C-Al-N system determine the quasibinary character (SiC) 1-x (AlN) x alloys. Inhomogeneous regions in (SiC) 1-x (AlN) x system were evaluated using the condition of mixing free energy minimum. We assumed that doping does not change the vibration spectra of the crystal.