Home – Home – Jornals – Chemistry for Sustainable Development 2006 number 3

Ion exchangers based on polyolefinic filaments remain poorly studied, though they are rather promising with regard to their well developed surface, good sorption capacity, mechanical strength, chemical and osmotic stability, etc. Moreover, there is a wide base of raw materials for their synthesis, and advanced modification methods may impart them quite unique properties. This review summarizes the most interesting data related to the properties and practical application of fibrous ion-exchange materials based on polypropylene and polyethylene.

Chemical modification of oxidized and weathered coals from the Shubarkol field (Kazakhstan) is studied. Coals are shown to be fit for the synthesis of amine derivatives via their interaction with amines (diamines) in the presence of acidic catalysts. Physical and chemical analysis data support the suggested synthesis scheme. Conductometric analysis method is developed for determining the functional composition of the oxidized coal modification products. It is demonstrated that nitrogen introduction into the coals improves their complexing ability and makes them polyampholyte. Sorption capacity of amine derivatives as pH function is shown to be a parabola with minimum at pH 4-5. This fact confirms the polyampholyte nature of these agents. Amino modified coals may be used for demineralization of mine waters and as extracting agents for metal ions precipitation from hydrometallurgy wastewaters.

Chromatography mass spectrometry was applied to study the qualitative and quantitative composition of pollutants in the working air of the Tie-Impregnating Plant (TIP) in the city of Taytshet (Irkutsk Region). Organic pollutants were shown to be provided by the emission of antiseptics, used in technology process. Pollutants composition varied depending on the sampling method and analytical sample pre-treatment. The most informative data were obtained, when sorption sampling was combined with extraction and thermal desorption sample pre-treatment for analysis.

Hard melting carbide and oxide barrier coatings over carbon and carbide silicon continuous fibres were studied with respect to their morphology, microstructure, composition and resistance to oxidation, as far as these fibres are meant for the arming of composites with ceramic matrix for construction purposes. Coatings are proved to show a good adhesion towards the fibres, and are longwise and crosswise uniform. Coating methods do not permit fibres splicing with each other. Fibres strength after coating remains the same or insignificantly decreases. Composites with carbon silicon matrix, armed with carbide silicon fibres with the interface coatings are characterized by expanded destruction viscosity, provided by the weakening of the fibres-matrix bonding and fibres stretching. Therefore, they may be used as construction materials in various fields, including atomic energy production.

Rate of hydrogen chloride desorption from the SiCl₄ and SiHCl₃ solutions was studied in time at gas end pressure P_total= 1.3 atm in a temperature range of 223-293 K. One may use desorption rate data for choosing better conditions for the HCl recover from chlorinated silanes.

Inversion voltammetry method was used to test 52 healthy people and 28 patients with Hodgkin's lymphoma (HL) (all Novosibirsk citizens) for the content of microelements such as Cu, Zn, Pb and Cd. In the blood and urine of healthy people zinc, lead and cadmium content was found to fit conventional norm, while Cu content in blood and its fractions was at the lowermost norm level. Copper content in the whole blood of the HL sick people insignificantly differed from that typical for healthy people. However, one of the main homeostasis parameters, namely copper and zinc balance in blood and urine, was disturbed. In particular, there was essential zinc deficit in blood, while in urine zinc was in excess. Moreover, all HL sick patients had insufficient cadmium excretion and blood lead deficit in comparison to the control group. Organic selenium containing, food supplement "Nutricon-Selenium" was clinically tested. Its administration brought zinc excretion to norm, but noticeably increased imbalance between copper and zinc in blood.

Processes of sorption and desorption of cesium and strontium radionuclides by main rock-forming minerals and soil samples from Kola PEN have been studied. It has been demonstrated that it is advisable that acidified solution of sodium chloride should be used to desorb radionuclides. A promising flow diagram has been proposed for deactivation of soils that have been polluted by radionuclides. The flow diagram involves a high degree of concentrating the radionuclides within a product to be buried, the use of a recycled solution that is intended for soil deactivation, as well as the freedom from the secondary pollution of soil by reagents harmful for the environment.

Processes involved in the interaction of some high-molecular compounds with the hydrazide of isonicotinic acid (isoniazid) and (+)-1,1'-ethylenediamine-N,N'-bis-(1-hydroxymethylpropane)dihydrochloride (ethambutol hydrochloride) in aqueous solutions are investigated. The deserving character of viscosimetry to be applied for the investigation of the formation of complexes of polymers with hydrophilic substances is validated for isoniazid and ethambutol hydrochloride. The data obtained are of special interest for the development of the chemistry of medications and for the elaboration of new highly efficient medical products.

For the first time the authors have shown the possibility to disintegrate phenacite-containing flotation concentrate by 93 % solution of sulphuric acid, which provides transformation of ~92 mass % beryllium from the concentrate to water-soluble sulphate. The further enhancement of the completeness of the concentrate disintegration up to ~98 mass % is ensured by application of mechanoactivating preparation of the concentrate for sulphatization.

The effect of nanofillers (nanocarbon, P-sialon and cobalt spinel) on the state of the interface of butadiene-nitrile caoutchouc (acrylonitrile content: 17-20 %) and ultrahigh-molecular polyethylene (UHMPE) is investigated. A set of physicomechanical tests was carried out, the characteristics of wear, oil and frost resistance of the investigated compositions were determined. It was shown that the use of additives allows one to improve the interaction and the interface of butadiene-nitrile caoutchouc and UHMPE and the performance characteristics of the materials based on these polymers.

Results of investigation of the process of lead cementation from its sulphate on powdered metals, namely, zinc dust and iron powder, under dynamic and static conditions have been presented. It has been demonstrated that the process runs more intensively without stirring. Kinetic characteristics of the process have been determined.

Ozonation of rubber crumbs, accompanied by the accumulation of oxygen in the inactive form, causes changes in the group composition of the products of thermal dissolution: the fraction of tarry matter increases, while the yield of gases decreases substantially. The amount of ozone-modified organic matter of rubber is estimated on the basis of the results of non-isothermal dissolution; the effective activation energy of the process is calculated.

Distribution of heavy metals in water, bottom silt, and on suspensions in the mouth area of the river and in the arms of the Selenga delta has been investigated. It has been found that significant part of Pb and Cu is sorbed on suspension. Cu, Fe, and Mn content in the water of the arms before the confluence into Lake Baikal increases in the spring and exceeds the admissible concentration limit for fish-economic water bodies. The analysis of seasonal dynamics of the content of elements in water demonstrates that maximal content of Pb, Zn, Cu, Fe, and Mn in water is observed in the spring and in winter; in the rest of the time of year, it flattens at a level of minimal autumn values.

The sorbents with layered-columnar structure were obtained on the basis of polyhydroxo complexes of aluminium and iron and the montmorillonite clay from the Mukhor-Talinskoye deposit. The texture characteristics of the sorbents were determined by means of low-temperature nitrogen adsorption and XPA. Their adsorption characteristics in aqueous solutions with respect to different anionic dyes were investigated. It was established that modification with polyhydroxo complexes of aluminium and iron causes an increase in the adsorption capacity of montmorillonite with respect to anionic dyes due to an increase in total specific surface and the number of anion-exchange centres.

Adsorption of bovine serum albumin by carbon fibres modified with titanium hydroxide by means of chemical and electrochemical deposition is investigated. The effect of fibre modification on changes in adsorption capacity with respect to the protein from the solutions of different composition is demonstrated. Adsorption of albumin was determined with the open-circuit potential and on the polarized surface of carbon fibres. Adsorption constants are calculated. It is established that titanium-containing fibre obtained as a result of the electrochemical deposition of titanium hydroxide is characterized by the maximal sorption capacity with respect to bovine serum albumin.

It is demonstrated for the first time that divinyl sulphide is a convenient and efficient monomer for the plasmachemical modification of the surface of various polymeric materials.