Home – Home – Jornals – Chemistry for Sustainable Development 2015 number 1

Literature data dealing with the major areas of application for polymers, copolymers and composite materials based on ion liquid monomers are considered and generalized. Polymers and copolymers based on ion liquid monomers combine the properties inherent to ion liquid monomers, in particular high ionic conductance, electrochemical stability, low inflammability and toxicity, as well as high thermal stability, with such features of high molecular mass compounds as the ability to form gel and films. Due to this fact, they are used as solid electroconductive matrices of various forms (films, fibres, coatings etc .) for batteries and fuel elements, membranes, sorbents for СО₂ capture, dispersing agents for stabilization of nanomaterials in various solutions (aqueous, organic). Non-volatility of ion liquids and polymer products based on them defines the promising outlooks for their use in making membranes to separate various gas mixtures. The dependence of ion conductance and sorption properties of polymers and copolymers based on ion liquid monomers on the nature of their cation and anion parts, as well as on the length of the fragments between the group participating in polymerization and the cation or anion part of the monomer was established. It was shown that the change of the structure of ion liquid monomer promotes broadening of the area of application of the polymers and co-polymers on their basis. In particular, polymers based on ion liquid monomers found application as a filling for the catalytic systems, coatings for semiconductors, for obtaining optical and plasma materials in the processes of solid-phase extraction and chromatography. So, the observed unique properties of polymers and copolymers based on ion liquid monomers promote expansion of investigations in the area of synthesis and polymerization of ion liquid monomers of various compositions and ensure the promising character of their application in many branches of industry.

It was established that the major pollutants of the river system at the territory of developed deposits in the Tomsk Region are oil and petroleum products the content of which in water exceeds the maximal permissible concentrations. It was demonstrated that space photographs and the data of remote probing Landsat and ASTER GDEM, SRTM may be used for the purpose of mapping the zones of oil spill, to determine the risk of pollution of water bodies, and to calculate the module of petroleum product washout from polluted basins in order to determine the total annual income in the river system.

Efficient technology was developed for obtaining water extracts and dry additive to mixed feed, containing a complex of biologically active substances, from larch biomass (wood and bark) processing. It was established by means of HPLC, UV, IR and ¹³C NMR spectroscopy that polysaccharide arabinogalactan dominates in the extracts. In addition, the extracts contain dihydroquercetin, tannins and other polyphenol compounds, as well as pectin compounds. Experimental lots of products were manufactured according to the developed technology; the efficiency of their use for growing young agricultural animals was demonstrated.

Photocatalytically active nanocompositions CeO₂-TiO₂ were prepared by means of sol-gel procedure from inorganic salts with different СеО₂/TiO₂ ratios. According to the data of X-ray phase analysis and optical reflection spectroscopy, in the case of CeO₂ content 5 mol. % and more, nanoparticles with fluorite-type lattice (CeO₂) are formed; the lattice spacing decreases with the insertion of titanium. In the case of low CeO₂ content (1 mol. %) TiO₂ nanoparticles are formed (anatase). Their optical properties are modified in the subsurface region. The obtained nanocompositions exhibit higher photocatalytic activity in comparison with individual oxides TiO₂ and СеО₂, and can be used to develop the systems of photocatalytic purification.

Humic acids (HA) obtained by the mechanochemical processing of peat and saw wastes at Khanty-Mansiysk Autonomous Okrug were studied for the first time by means of ¹³C NMR spectroscopy. Differences in the functional composition of the resulting humic acids depending on the type of base used and the chemical composition of the secondary plant raw material were revealed. The reasons of the increased physiological activity of humic acids obtained as a result of sanitation of the secondary plant raw material in water-alkaline media were established.

The products of thermolysis of brown coal from the Baganur deposit (Mongolia) were investigated. Only residual relics of separate hydrocarbon components of initial coal were detected in the solid residue. The liquid condensate of the sublimates (18–19 % of initial coal), which contains 0.78 mass % organic extract (96–98 % phenol and its derivatives) and 92.2 mass % of the aqueous solution, under heating boils off within temperature range 115–130 ^оC. The isolated organic extract under heating is transferred into vapour intensively at temperatures up to 360 ^оC. Initial aggregative state (particle size, degree of the action of environment) not only affect the yield of the gas component of coal during thermolysis but also determine the impurity composition of the organic extract of the liquid condensate of sublimates.

Recovery of low mass molecular copolymers based on styrene and unsaturated compounds, present in the bottoms from the purification of recurrent solvent of polybutadiene production, in the presence of aluminium chloride was investigated. It was shown that the toluene solution of low molecular mass copolymers can be used in the production of polybutadiene for the preparation of antioxidant solution.

Hydrolytic lignin is transformed almost completely into liquid (lingo-oil) and gaseous products under the conditions of thermocatalytic hydrolysis and alcoholysis, in particular in combination with hydrogenolysis. The liquid fraction is a mixture of alkyl– and methoxyphenol, esters of carboxylic acids, aliphatic and aromatic hydrocarbons. These products are formed as a result of the destruction of lignin polymeric matrix mainly at С–О bonds. In addition, depolymerisation of lignin proceeds with substantial decrease in oxygen concentration in the formed liquid products (to 5–10 %) in comparison with that in initial lignin (30 %). Gaseous products contain carbon oxides and lower hydrocarbons (С₁–С₅).

Sorption of 1,1–dimethylhydrazine by hydrolytic lignin was studied by means of gas chromatography–mass spectrometry. The effect of sorbent humidity and temperature on sorption was investigated. The kinetic and thermodynamic parameters of the process were determined. It was demonstrated that hydrolytic lignin may be used as a sorbent to prevent air pollution in case of detoxication of spilled highly toxic rocket fuel.

The elemental composition of the bark of Siberian buckthorn (Hippophae rhamnoides L. ssp. mongolica Rousi ) growing under endemic conditions of West Siberia was studied. The simultaneous quantitative content of K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Pb in bark and in soil was determined by means of XPA–SR (X–ray fluorescence analysis involving the synchrotron radiation), and the coefficients of biological accumulation of these elements were established. Species-specific features of the absorption of elements in the bark of Siberian buckthorn were revealed, which is expressed as increased (in comparison with the earth's phytomas) accumulation of vitally necessary iron, molybdenum and chromium, as well as elements with unestablished biological role: niobium, titanium and zirconium. It was shown that the bark of Siberian buckthorn can serve as a source of vitally necessary chromium in the easily digestible biogenic form. It was established that the bark of Siberian buckthorn does not concentrate toxic chemical elements — lead and arsenic.

A method of obtaining ceramic membranes containing carbon nanotubes (CNT) is proposed. Gibbsite is thermally activated using the industrial method, and then it is mixed with the CNT–SiO₂ composite and lanthanum hydroxide. The resulting mixture is subjected to mechanochemical activation and plasticized with the help of the aqueous solution of nitric acid. The resulting mass is evaporated to the semi–dry state and pressed in the press mold under a pressure of 100 MPa. The pressed tablets of the composition 80 mass % Al₂O₃ + 17 mass % (CNT–SiO₂) + 3 mass % La₂O₃ are annealed under anaerobic conditions under smooth heating to a temperature of 950 °С. Sintering and transformation of initial oxide phases were studied under usual heating in a muffle furnace and under heating through energy input by means of microwave frequency radiation directly to the initial samples Under the microwave heating of the resulting membranes, a stronger transformation and sample agglomeration are observed than those related to the case of heating in a muffle furnace.

A method of electrochemical purification of aqueous solutions from metal ions is proposed. The method is based on the use of electrochemical cell separated by a passive membrane, and substitution of metal ions by hydrogen ions. The conditions enhancing the effects of concentrating and removal of metal ions form solutions with low concentrations of the salts of weakly and strongly dissociating acids are determined.

The isotherms of zinc adsorption from solutions on natural and modified montmorillonites were recorded. It was shown that adsorption processes can be described with the help of Langmuir and S-like adsorption isotherms; their shape is determined by both the properties of sorbent surface and the forms of zinc occurrence in aqueous solutions. Intercalation of the sodium form of montmorillonite by modifying agents allows a sharp increase in limiting adsorption of zinc ions and broadening of the pH value region corresponding to the high degree of metal recovery.

Autoclave-free and low-temperature method of obtaining liquid glass from modified silica gel is considered. Silica gel, a side product of the production of aluminium fluoride, is amorphous silicon dioxide with admixture of fluorine and aluminium compounds. The methods of silica gel processing into liquid glass with preliminary acid purification from admixtures are analyzed. The physicochemical composition of silica gel was studied by means of IR spectroscopy and X–ray phase analyse. Activation of silica gel with the use of alkaline solution was used to increase the yield of liquid glass and the silicate modulus of liquid glass. The dependence of aluminium content in silica gel on the concentration of alkali in the activation solution was established. It was discovered that the yield of liquid glass is determined by the concentration of admixtures in activation solution. The effect of the concentrations of F^– and SiF₆^2– ion content in activation solution on the silicate modulus of liquid glass was studied. It was concluded that it is reasonable to apply alkaline activation solution to obtain liquid glass from silica gel. The dependences of silicate modulus of liquid glass, its density and yield on temperature and time parameters are presented.

Transparent conducting thin film coatings based on tin oxide doped with fluorine SnO_2-хF_х were obtained by pyrolysis of aerosol. The coatings are characterized by nanocrystals structure with average particle size 14 nm. The kinetic dependences of the changes of film resistance were studied in situ during an increase in coating thickness. The major stages of the film growth process were determined. The regimes of obtaining transparent SnO_2-хF_х films with specific conductance more than 10³ S/cm were elaborated.