Home – Home – Jornals – Chemistry for Sustainable Development 2008 number 2

Sorption of Cu²⁺ and Zn²⁺ cations from model solutions by humic acids that were extracted from oxidized brown coals of Gusinoozyerskoye deposit has been investigated. An effect of pH value on the extraction of Cu²⁺ ions has been considered; sorption isotherms of Cu²⁺ and Zn²⁺ ions have been plotted. Maximum sorption exchange capacities of humic acids have been calculated on the basis of the Langmuir isotherm equation

Physical and chemical features of natural clays have been studied using the methods of X-ray diffraction, chemical, thermal and spectral analyses, ESR and IR spectroscopy; the nature of their medical properties being considered. The composition of macro and trace impurities in the clays has been analysed. The medical properties of the clays are determined by the presence of almost all the chemical elements necessary for normal functioning of a living organism as well as by sorption features due to a specific character of crystal structure. Using ESR technique, the forms of occurrence for some trace impurities (Mn²⁺, Fe³⁺) and for paramagnetic centers (PC) of the radiation nature have been determined. The intensity of PC response has been shown to correlate with the content of actinoid ions such as U and Th in the samples. Basing on the ESR spectral data it has been established that blue color of the clays is caused by V⁴⁺ impurity ions V⁴⁺ in the form of vanadyl VO²⁺. The content of the microelements such as vanadium, boron and chromium in blue kaoline глинах has been demonstrated to be 10-15 times higher as compared to clay samples of another coloring. An important role of complex influence of macro- and microelements (silicon-boron, vanadium-chromium, manganese, etc.) on the enzymes and hormones in various organs, as well as the presence of such combinations of chemical elements in blue clays have been noted.
Keywords: natural clays, physicochemical features, medical properties

Determination of the polycyclic aromatic hydrocarbons (PAH) accumulated in the needle of a Scotch pine (Pinus sylvestris L.) was for the first time carried out over the Baikal Natural Territory (BNT). It has been established, that in the industrial and urbanized territories of the BNT the level of PAH accumulation in needle amounts to as much as 1800 ng/g, whereas the background regions of BNT this value is less than 20-60 ng/g. The composition of PAH accumulated includes a priority series of organic pollutants from this class. The investigation of different age needle has demonstrated that the needle of the second year could be considered as an adequate bioindicator of atmospheric pollution. The levels of PAH accumulation in pine needle indicate a local character of atmospheric pollution over the southern part of BNT, as well as an insignificant contribution of regional transfer of the mentioned pollutants to the pollution of the Baikal lakeside comparable with the background level. The comparison of PAH content in the needle with the suppression degree of pine timber-stands allows one to assume these pollutants to exhibit a phytotoxic effect.

Processes of crystallization of calcium oxalate monohydrate from aqueous solutions and the effect of amino acids on these processes were investigated. It is shown that amino acids inhibit the growth of crystals of the compounds under investigation; the inhibiting action of an amino acid depends on its structure and increases with an increase in its concentration. The inhibiting effect on the crystallization of calcium oxalate monohydrate is also produced by magnesium ions in the concentration corresponding to the physiological solution (urine). It is demonstrated that the presence of hydroxyapatite crystals in solution initiates the crystallization of calcium oxalate monohydrate.

Iodine content within abiotic components and plants of Transbaikalian landscapes has been studied. A low iodine reserve of soil-forming rocks, natural waters, soils and plants has been revealed. A possibility has been studied for enriching plants with iodine by means of iodine micro-fertilizing.

The interaction of oxohydroxobismuth (III) nitrate trihydrate with the solutions of gallic acid was studied by means of X-ray phase analysis, thermogravimetry, IR spectroscopy and chemical analysis. The effect of temperature of pH of the medium on the rate of the exchange of nitrate ions for gallate ions was studied. The conditions of the formation of bismuth oxogallate trihydrate having the composition C₆H₂(OH)₃COOBiO · 3H₂O were investigated. The reasonability of the synthesis of high-purity bismuth oxogallate through the interaction of oxohydroxobismuth (III) nitrate trihydrate with the solution of gallic acid was demonstrated.

A combined method is proposed for the degradation of chlorophenols in a flow-through photoreactor using an UV XeBr* excilamp (283 nm) and the subsequent processing of the photolysis products by a destructor microorganism Bacillus cereus culture isolated from the aeration pond of the Baikal Pulp and Paper Mill. The maximum efficiency for the degradation of chlorophenols amounts to 95 %, thus the utilization of main photolysis products is achieved.
Keywords: chlorophenols, degradation, excilamp, photolysis products, microorganisms

Reactions of CH₃NH₂HCl with MBH₄ (M = Li, Na, K) proceeding during mechanical activation of the mixtures of crystal substances in a vacuum ball vibratory mill are investigated. It is established that the stage-by-stage pyrolysis of reaction products at 100 ^oC, then at 200 ^oC results in the formation of N-trimethylborazine (CH₃NBH)₃. Maximal yields of N-trimethylborazine with LiBH₄, NaBH₄ and KBH₄ are 60, 34 and 36 %, respectively. Melting points, saturated vapour pressure, density, refractive index of N-trimethylborazine are determined; the IR spectrum is reported.

Fatty acid composition of Siberian marmot fat (Marmota Sibirica, tarbagan) has been studied; the basic physicochemical parameters have been determined. 36 fatty acids have been identified, about 90 % among those being represented by palmitic, oleic, linoleic and linolenic acids. A comparative analysis of the compo-sition of tarbagan's hypodermic, abdominal and brown fat was carried out. It has been established that for the kinds of fat under investigation the composition of acids is variable, and the greatest differences in the concentration of saturated acids are inherent in brown fat. An unusually high fat unsaturation level for land species of animals observed for a Siberian marmot might cause the fat biological activity.

The effect of gas-phase ozonization on variation of chemical composition of solid combustible minerals of various genetic types and petrographic composition of brown coal maturity and products of their basic hydrolysis has been investigated. It was found that directions of oxonolytic transformations of organic matter as well as the yield and componental composition of products of alkaline extraction of coals are governed by features of their molecular organization. Reactivity of combustible minerals in relation to ozone increases with an increase in the H/C atomic ratio.

By means of mesomodeling method it has been established that the variations of рН, dissolved organic substances added and herbicide in polluted natural waters can significantly influence Cu, Pb and Cd distribution between aqueous phase and suspended substances. The changing of these parameters is reflected by the rate of withdrawing the mentioned heavy metals to bottom sediment. So, given lowered pH and concentration of dissolved organic substances as well as the presence of herbicide components in water the rates of Cu, Pb and Cd withdrawal to bottom sediment decreases. An assumption has been made that such a distribution depends on the state of heavy metals in the aqueous phase

The porous properties of silica prepared from heat-treated Transvaal vermiculite (South Africa) by acid leaching were determined. The effect of temperature on the destruction of the crystal structure of the vermiculite was determined, leading to the adoption of heating conditions of 600 ^oC for 2 h which produce a fully amorphous sample. The heat-treated samples were leached with 2 M hydrochloric acid at 80 ^oC for 0.5, 2 and 8 h and their porous properties were characterized by measuring their specific surface areas and pore volumes. The highest surface area and pore volume (559 m²/g and 0.51 ml/g) was obtained for the sample leached for 8 h. Thermal amorphisation of vermiculite exerts a negative influence on the porous properties of the mineral.

Time-space estimate of a level of mercury pollution of Altai atmosphere has been performed according to layer-by-layer analysis of high mountain glacier core sample that was taken by joint Russian-Swiss expedition in 2001 in a saddle of Belukha Mountain of the Altai hills (Katun ridge, Altai). The results arrived at have demonstrated that mercury content of glacier layers that had been shaped during the industrial time varies within the limits of 0.2-6.3 ng/kg and it is comparable with mercury level of alternative high mountain glaciers of the Northern hemisphere. Data of the layer-by-layer analysis of glacier core sample for a period of 1940 to 2001 testify that Aktash Mercury Integrated Works, a large local source of mercury, exerts no significant effect on the pollution of the atmosphere of the Western Altai. A calculation technique has been suggested to quantitatively estimate the regional component of mercury pollution of a territory. It has been found that the contribution of the regional component almost 3.5 times exceeds the contribution of the global component to the total present-day level of the pollution by mercury of the atmosphere of the Altai (Central Asian) region. A conclusion has been made that Altai-Sayan mercury province and industrial metallurgical centres of East Kazakhstan may act as the main sources in terms of the regional level of mercury pollution of the atmosphere of northwest part of the Altai territory.

Fundamental potential of single-stage processing of ilmenite concentrate to synthetic rutile of commercial quality has been shown experimentally and by thermodynamic computations. The method has its origins in selective chloridation of iron and impurity of magnesium, chrome, manganese, sulphur, and vanadium by chlorine with no use of any reducer. Possibility to extract vanadium without reduction smelting and without loss of titanium and other target ingredients of the concentrate was revealed for high-titanium titanomagnetite concentrate. The other target ingredients can be later isolated by the reduction chlorination. It has been found that the great bulk of iron and vanadium can be extracted from titanium concentrates for 10 min at a temperature of 1373 K and under atmospheric pressure.

Principal tendencies of variation in crude oil composition and properties during thermolysis under laboratory conditions have been studied by the example of heavy, high-viscosity crude oils from Usinsk and Lyaokhe oil fields. The experiments were conducted in an autoclave of periodic action in a range of temperatures 200-350 ^oC with addition of water and with application of a mineral admixture to study the nature of the influence of oil-bearing rock. Thermolysis products are represented by gases, insoluble carbonisation products, and converted oil. It has been found that the content of nitrogen, sulphur in liquid products of thermolysis differs from that for initial crude oils, the content of asphaltenes grows, the proportion of resins and oils decreases. Proportion of nitrogen bases, aromatic and oxygen-containing structural fragments in the composition of aquathermolysis products increases, amides appear in it. Specific absorption index of oils and their fractions at a wavelength of 500 nm tangibly change together with individual composition of alkanes and naphthalenes. Tendencies of variation in key parameters of composition during the aquathermolysis of Usinsk oil and crude oil from Lyaokhe oil field are quite opposite. The effect of mineral admixture on the results of thermolysis manifests itself only at the level of liquid yield, of their elemental, group, and functional (according to IR spectra) compositions and it is imperceptible at the level of functional group composition and at the level of individual composition of compounds that were identified in these oils