Home – Home – Jornals – Chemistry for Sustainable Development 2012 number 5

Results of the mineralogical and geochemical investigation of technogenic aerosol samples collected in 2011 in the northeastern direction from Novosibirsk in the plume of the Novosibirsk Chemical Concentrates Plant JSC, as well as aerosol collected near the Novosibirsk Tin Plant JSC and Heat and Electric Power Plant No. 3 are reported for the first time. Uranium content and its mineral formations were determined by means of ICP-MS, ICP-AES and scanning electron microscopy.

Ground water in the region of slurry dumps of low-activity wastes from the Angarsk Electrolysis Chemical Combine manufacturing enriched uranium was studied. It was established that the E_h values vary from weakly reductive to oxidative, pH varies from neutral to alkaline values. The presence of a hydrodynamic mound in the region of the slurry field provides vigorous diffluence of the technogenic infiltration runoff, which results in possible local increase in the concentrations of , and in the zone of the hydrodynamic mound above the maximum permissible level. Alkaline sodium nitrate solutions are characterized by higher salt content (up to 9 g/L) but uranium content of all the ground water samples (background, in the region of the stores of solid and liquid radioactive wastes) is below the MPC level. The composition of phases that are able to precipitate from the disposed slurry water after neutralization with Са(ОН)₂ and settling was confirmed with the help of thermodynamic calculations. Possible increase in the concentration of uranium in the interaction of calcium urinates with CO₂ (solution) was demonstrated. Limiting concentrations of uranium in solutions were calculated; the limiting values are determined by the s9lubility of uranium-containing minerals formed depending on pH, partial pressure of СО₂ and the presence of cations (Ca, Si, Al).

Results are presented for hydrogeochemical monitoring the industrial area of the JSC “Novosibirsk Chemical Concentrates Plant” as well as experimental data concerning the demercurization of soils and building materials those were contaminated with mercury. A comprehensive approach to the demercurization and geological conservation of mercury-containing waste is proposed that includes three stages: 1) a centrifugal extraction of mercury from solid wastes including contaminated grounds, soils and building refuse; 2) chemical immobilizing the mercury remaining in the insoluble form (naturally occurring mineral Stchuettite); 3) geological conservation.

Dependence of the properties of calcium phosphate compounds on the method of their isolation from biological raw material was studied. Physicochemical studies of the properties of resulting materials were carried out. The proposed procedure allows one to obtain ultrafine powders of biological hydroxyapatite with controllable particle size and composition maximally approaching the composition of bone tissue. It was established that the calcium phosphate compound deposited from the solution that was obtained by demineralization with the solution containing hydrogen chloride 1 mol/L is most close to the mineral matrix of bone tissue.

Physicochemical properties inherent in chitosan-containing solutions as well as the sorption properties of carbon materials modified with chitosan were studied. It has been found that the composites obtained exhibit anion-exchange properties. The chitosan-containing materials have been shown to exhibit a sufficiently high sorption capacity, which makes them efficient as sorbents for the concentration and extraction of gold, and other heavy and radioactive metals in the future.

Cerium sulphate ion-exchange sorption by containing naturally occurring clinoptilolite tuff from aqueous solutions was studied within a wide range of concentration values (10^-5-10^-2mol/l). Adsorption isotherms and kinetic parameters have been determined.

An effect of different methods for aspen wood activation (grinding in the mills of different types, explosive autohydrolysis, catalytic oxidation by hydrogen peroxide and the combination of these methods) exerted on the structure, chemical composition and reactivity of activated wood was studied. It has been found that all the methods of aspen wood mechanical pretreatment result in changing the supramolecular structure, chemical composition and reactivity thereof: activated samples exhibit increasing the content of readily hydrolysable polysaccharides, with reducing the concentration of polysaccharides difficult to hydrolyze and of residual lignin, as well as with increasing the rate of polysaccharide acidic hydrolysis into monosaccharides and the rate of lignin oxidation by hydrogen peroxide.

Phase formation was studied for the systems of Cyanex 301 (bis(2,4,4-trimethylpentyl)dithiophosphinic acid)–organic solvent (toluene, heptane, octane)–sodium hydroxide–water–trioctylamine. It is demonstrated that the Cyanex 301 transition into a salt form (three-phase extraction) results in achieving the separation of the organic extraction agent solution into the solvent phase and a cation-exchange extraction agent. The sodium salt of Cyanex 301 is almost completely transformed into a new aqueous micellar solution. Conditions have been determined for the efficient separation of the organic phase components and for the isolation concentrated Cyanex 301. An effect of trioctylamine additives exerted on nickel extraction in the systems with Cyanex 301 was studied. A scheme has been proposed for the extraction of nickel using a three-phase extraction, wherein nickel is extracted by means of the concentrated solution of Cyanex 301 from acidic solutions resulted from leaching the ore, the extract is mixed with an organic amine solution to be re-extracted with sulphuric acid, whereas the organic phase is separated into initial components via treatment by sodium hydroxide solutions.

The interaction of bismuth (III) citrate BiC₆H₅O₇ with the aqueous solutions of potassium hydroxide in different concentrations was studied by means of X-ray phase analysis, IR spectroscopy, thermogravimetry and chemical analysis. The conditions for the formation of the potassium salt of bismuth (III) citrate having the composition KBiC₆H₄O₇ · H₂O were determined. Reasonability of obtaining this compound through the interaction of the aqueous solution of potassium hydroxide with bismuth (III) citrate with their molar and mass ratio equal to 1.0 was shown.

Modifying the low-calorific lignite from the Sergeevo deposit by means of liquid-phase catalytic alkylation with isopropyl alcohol was performed. The basic processes involved in the interaction of the coal under investigation with isopropyl alcohol were described. A positive effect of the alkylation treatment exerted on the coal bituminosity, the componential composition and the physicochemical characteristics of modified products obtained has been revealed.

Via the reaction of alkaloid cytisine, l-ephedrine, d-pseudoephedrine as well as glucosylbenzylamine and xylosylbenzylamine aminoglycosides with vinyloxyethylisothiocyanate and its acetal derivatives, we synthesized and characterized novel 2-vinyl-, N-1-propargyl-, 1-N-phenyloxyethoxyethylo-N’-aminothiourea species. By the example of the N-vinylethoxythiocarbamoyl derivatives of l-ephedrine and d-pseudoephedrine is demonstrated that the mentioned thiourea species could quite readily undergo hydrolyzing in the presence of acids. On the basis of salicylic acid hydrazide we have synthesized and studied the acidic hydrolysis of corresponding vinyloxyethylthiosemicarbazide. The composition and the structure of the thiourea derivatives synthesized were confirmed by IR spectroscopy, ¹H NMR, ¹³C NMR and mass spectrometry as well as by XRD structural analysis.

Results of the comparative analysis of the effect of oxidative modifying performed using ozone, nitrogen (I) oxide and low-temperature oxygen plasma, on the chemical composition of coal from the Khushuut deposit (Mongolia) and its ability to thermal destruction are reported.

The content of acetate ions in the blood of patients after cardiac surgery in the course of hemodialysis using different dialyzing solutions was investigated for the first time. Using the method of capillary electrophoresis it was revealed that in the case when the bicarbonate dialysate contains acetate ions in a small amount (3 mmol/L), the concentration thereof in blood exhibits a 12-fold increase, which causes enhancing the risk of cardiovascular instability in  the course of hemodialysis.

Studies were performed concerning the seasonal dynamics of major ions (Na⁺, Mg²⁺, K⁺, Ca²⁺, SO₄^2-, Cl^-, HCO₃^-), Si, 52 trace elements, organic carbon, pH, O₂ in the Selenga River, the main tributary of Lake Baikal and the rivers flowing into the Selenga in the Russian territory, the flow paths and lakes of the delta within the barrier area of Lake Baikal (up to 7 km from the mouth of the Selenga River). Using the factor analysis we revealed four main groups, those differ from each other in the spatial and temporal distribution of the components in the Selenga River. The first group comprises the water salinity, the major ions and trace elements, some conservative trace elements (B, Br, Sr, Mo, Ba, Re, U). The concentration values for these components are maximal within the ice period (March) and minimal within the flood period (May), exhibit an increase on the frontier with Mongolia reducing towards the mouth as being diluted by less saline water of the tributaries of the Selenga River. The elements of the second group are connected with the content of dissolved organic matter capable of mobilizing difficultly soluble and almost insoluble elements (Be, Al, Ti, Fe, Ni, Cu, Ga, Y, Zr, Nb, Hf, REE, Pb, Th) to produce fine-dispersed organomineral complexes. The concentration values for these elements demonstrate increasing in the spring, in the course of the snowmelt and of an active removal of organic matter from the catchment area. The third group of the elements (Si, Li, Cr, Mn, Co, Zn, Ge, Rb, Ag, Cd, Sn, Cs, Bi) reflects the processes of water acidifying against the background of seasonal dynamics inherent in the dissolved oxygen. Concentration values for these elements increase towards the mouth (except for Co within the period of spring and autumn, as well as Ge in winter), being to a significant extent increased in the winter. The fourth group of the elements (V, As, Sb, I, W, Cu) represents a marker of a weak cross-border transfer in summer. Increased concentration values of these elements are observed in July, especially on the upper section of the river (0–120 km from the frontier with Mongolia). The maximum and average weighted concentrations of the most of trace elements in the Selenga River are lower than those inherent in the global natural river background. Exceeding the maximum background concentration values is observed for Mo (10 %), Mn (10 %) and Ge (60 %). Average weighted background concentration values exhibit a 2- to 5-fold exceeding in Zr (2.1), Nb (2.1), Sr (2.5), Ti (2.9), U (3.5), Y (3.5), Zn (3.7), Mo (3.8) and Sn (4.9), which could be caused by the geological structure of the basin and the naturally occurring processes of mobilizing the elements. The concentration of Mo, Mn, Cu, Al, Fe, V in the general river station of the Selenga River and the tributaries thereof in some seasons are slightly higher than Russian standards established for fish-industry water basins (in 80 % of cases less than 2 MPC). Within the barrier zone of Lake Baikal there is an excess over the fish industry water standards in Mo registered to be constant (1.2–2.1 MPC): for Cu in winter (up to 1.8 MPC), in summer (up to 1.9 MPC), in autumn (up to 1.3 MPC); for V in summer (up to 1.6 MPC); for Mn in winter (up to 2.2 MPC).

Chemical composition of the light fraction (Т_boil ≤ 300 °C) of heavy pyrolysis tar (HPT) was studied; more than 40 components were identified. The content and nature of the still bottoms of HPT were determined. It was established that the method of HPT processing is determined mainly by the concentrations of naphthalene, unsaturated compounds and still bottoms. The processes of HPT polymerization with the application of radical type initiators dicumyl peroxide and di-tert-butyl peroxide (DTBP) were studied. New grades of petroleum polymer resins (PPR) with high softening temperature were developed; they can be used in rubber-processing industry. A method of HPT processing using the still bottoms of styrene rectification and DTBP, followed by evaporation of volatile components, was proposed for obtaining PPR with required properties and the yield up to 68 %.

Effect of the mechanical activation of rice husk on the progress of subsequent enzymatic hydrolysis was studied. It was established that mechanical treatment promotes an increase in specific surface area, destruction of the silica shell coating lignocellulose, and substantial amorphization of the crystal regions of cellulose. As a result, the degree of conversion of polymer carbohydrates into soluble saccharides increases practically by a factor of 13. So, mechanoenzymatic treatment of rice husk allows one to obtain carbohydrate-containing intermediate product that may be used for further microbiological processing.