Home – Home – Jornals – Chemistry for Sustainable Development 2014 number 5

The first results of the granulometric studies of nano– and microparticles of atmospheric suspensions in snow samples collected in winter 2012–2013 at the territory of Botchinsky reserve are presented. It is shown that the snow samples from five sampling stations contain nano- and microparticles of metal compounds (W, Ti, Fe, Ba, Sn, Zn, Zr, Ag, Ce, La) of technogenic origin, as well as increased concentrations of water-soluble compounds of some metals (zinc). In the samples from two sampling stations (the valleys of the Mulpa and the Botchi) the fraction of particles with the size 1–10 mm is 100 %.

Qualitative and quantitative composition of polycyclic aromatic hydrocarbons was studied in the samples of snow water in Novokuznetsk. The distribution of these hydrocarbons between the solid and liquid phases was studied by means of high-performance liquid chromatography. The maximal content of carcinogenic and toxic PAH was detected in the samples of snow water from the Kuznetsk region: it exceeds the MPC for benz(a)pyrene by a factor of 72.3. The concentrations of toxic elements in snow water samples were determined b y means of atomic emission spectroscopy with inductively coupled plasma. It was shown that the concentrations of a number of toxic elements (Al, Cu, Mn, Fe) in snow water exceed MPC adopted for surface water. Particle size distribution for the suspended matter of snow water was studied by means of laser granulometry. It was established that 90 % of suspended matter in snow cover is represented by the particles with the size not more than 35.5 mm.

Preliminary mechanical treatment of a mixture of yttrium oxide and lithium carbonate in a planetary mill intensifies subsequent thermal synthesis of LiYO₂ and allows reducing the temperature of complete transformation to 850 °C. The synthesized powder can be used as an additive that accelerates sintering of aluminium nitride without additional grinding. Mechanical treatment of the mixture results in the formation of aggregates that are frameworks of Y₂O₃ filled with lithium carbonate. Due to this, the surface of contact between reagents increases. However, with excess over some limiting acceleration developed in the mill, the framework densifies, and extrusion of the second component is observed. As a consequence, the reactivity of the mixture decreases, especially if lithium carbonate is changed for hydroxide. in this connection, mechanical treatment of the mixture under the same experimental conditions is unreasonable. The mixture obtained by precipitation from solution without mechanical treatment allows carrying out the synthesis even at 700 °С.

The properties of refined hydrotropic cellulose and cellulose nitrates synthesized using the commercial sulphuric-nitric mixture were studied. In spite of the high content of non-cellulose components, the obtained cellulose nitrate samples are close in their characteristics to highly viscous colloxilin. It was established by means of IR spectroscopy that hydrotropic cellulose is identical to classical cellulose in characteristic frequencies, while the products of its synthesis are cellulose nitrates. The morphology of hydrotropic cellulose and its nitrates was characterized by means of scanning electron microscopy.

Results of integrated high-resolution NMR studies of operating changes of motor oil of Texaso Company (the USA) for diesel engines of automobiles are presented. It is shown that a number of the chemical characteristics of oil change during operation: the degree of aromaticity, the ratio of methyl to methylene group content, content of phosphorus–containing additives. Qualitative and quantitative analysis of phosphorus–containing additives was carried out, the adaptation mechanism of the response of oil additive was revealed. The promising character of the use of NMR spectroscopy in monitoring-based analysis of motor oil was demonstrated.

Physicochemical regularities of the surface oxidation of materials made of polypropylene, polyethylene and their wastes were studied as the method to make secondary polymer materials. The properties of the obtained samples were studied. A comparative analysis of the results of modification of the wastes of fibrous and film materials of polyolefins using different methods (oxidation with atmospheric oxygen in the aqueous medium, in the gas phase, ozonation) shows that the simplest and the most efficient method is non-initiated solid-phase thermal oxidation with atmospheric oxygen.

The features of the modern state of soil in Cheremkhovo city (Irkutsk Region) and adjacent territories are demonstrated. The high level of soil pollution with heavy metals was revealed. The results of sanitary microbiological analysis provide evidence of soil pollution with communal and household organic substances and allow evaluating the state of soil as close to epidemically dangerous one.

The effect of highly viscous petroleum from the Tzagaan Els deposit (Mongolia) on the oxygenase activity of indigenous soil microflora was studied. It was shown that after the adaptation of microorganisms to hydrocarbons their number increases by two orders of magnitude, while the enzymatic activity increases by a factor of 2–3. Utilization of viscous petroleum during 180 days of experiment is 78 %. Analysis of petroleum after biodegradation showed that it contains a large number of oxygen-containing compounds — intermediate products of oxidation during microbiological assimilation of petroleum hydrocarbons. In the composition of highly viscous petroleum, all hydrocarbons are affected by the biochemical oxidation by soil microorganisms.

It is shown that insulation of masout soil pollution with a bulk layer of pure sand may cause its contamination. The migration of the pollutant against the force of gravity occurs through the mechanism of capillary rise in the case of low moisture content in the pore space, and in water–saturated horizons this occurs also due to the difference in the densities of masout and water.

Urgency of the studies aimed at the development of ecologically safe, naturally biodegradable polymer materials including biopolymers of natural origin — polyhydroxyalkanoates — is demonstrated. Short– and medium–chain samples of polyhydroxyalkanoates of the new chemical structure with different combinations of the fractions of 3– and 4–hydroxybutyrate or 3–hydroxyhexanoate were obtained. The physicochemical and mechanical properties of copolymer samples of polyhydroxyalkanoates were studies.

Electrocatalytic activity of the alloys of (TiCr_1.8)_1–xV_x system in the reaction of hydrogen evolution was studied by means of polarization curves, electrochemical extraction and impedance spectroscopy. Parameters characterizing sorption properties of alloys under the conditions of electrochemical saturation were determined: the amount of absorbed hydrogen, effective diffusion coefficient, thickness of diffusion zone.

Comparative analysis of interstitial water in organic sapropel (0–167 cm) formed during middle Holocene for 5100 years, and the surface water of Lake Dukhovoye (Southern Pribaikalia) was carried out. Transformation of hydrocarbonate calcium–sodium–magnesium lake water into hydrocarbonate–sulphate interstitial water of sapropel is observed. It is established that mineralization of interstitial water increases with depth, that is, the transition from ultrafresh surface water to fresh interstitial water of organic sapropel occurs. Interstitial water is enriched with almost all the studied ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^– and Cl^–) and elements (Al, Fe, Mn, Pb, Cd, Zn, Cu, Ni and Co) in comparison with surface water. The series of element mobility show that the mobility of some elements changes substantially in the section of sapropel of Lake Dukhovoye. In surface water Na, K, Ca, Mg, Mn, Cd and Zn dominate in aqua ion forms, Al and Fe in hydroxide complexes, Pb and Ni in carbonate complexes, Cu in fulvate, hydroxide and carbonate complexes. The fraction of aqua ion forms of Na, K, Ca, Mg, Mn, Cd and Zn in interstitial water of sapropel decreases with depth, while the fraction of sulphate complexes increases. Redistribution of forms in comparison with surface water occurs.

Catalysts containing lanthanum and zirconium oxides were prepared on the basis of zeolite of ZSM–5 type using different preparation procedures. The effect of promoting additive and the method of zeolite modification on their catalytic and physicochemical properties in the process of obtaining dimethyl ether from synthesis gas was studied. It is demonstrated that the introduction of the modifying agent by impregnation causes an increase in the yield of target product in comparison with non–modified sample by a factor of 1.7 and 1.8 for zirconium– and lanthanum–containing catalysts, respectively. The optimal conditions of the process were determined.

Estimation of the amount of stratospheric hydrogen chloride HCl necessary for the formation of the spring ozone hole was carried out during the period of its existence above McMurdo station in 1992 on the basis of the maximal concentration of ClO in lower Antarctic stratosphere. The height of gas plume emitted by the Antarctic volcano Erebus during active degassing was calculated, as well as the trajectories of further cyclonal elevation of these emissions inside high cyclones to the height of more than 18 km, obtained using the NOAA HYSPLIT model. It is demonstrated that the fraction of volcanic emissions reaching the height of the stratosphere averaged per year is 41.5 %. It is established that the amount of volcanogenic HCl entering the Antarctic stratosphere every year is sufficient for the formation of the ozone hole of modern scale. It is shown that anomalous enhancement of the activity of Erebus in early 1980es became the key factor for the substantial increase of the Antarctic ozone anomaly. A decrease of the size of the spring ozone hole above Antarctica is possible only in the case of sharp decrease or complete termination of the activity of this volcano.