Vladimir Ogenko

National Academy of Sciences of Ukraine | ISP · Department of physico-inorganic chemistry

Modification of tubular ceramic membranes made of clay minerals is carried out. The membranes are modified with pyrocarbon, which is obtained by carbonization of organic-polymer precursor at 750С in an argon flow. The carbonation precursor is synthesized from a polyisocyanate and aque-ous solution of milk powder, which is introduced into the membr...

Modification of tubular ceramic membranes made of clay minerals, which were obtained by slip casting (produced by the Dumansky Institute of Colloid Chemistry and Water Chemistry of the National Academy of Sciences of Ukraine) was carried out. The membranes were modified with pyrocarbon, which was obtained by carbonization of a precursor – poly(uret...

The tubular ceramic membranes of clay minerals were modified with silica and pyrocarbon, which were obtained by carbonization of organic-inorganic composites at 800 °С in an argon flow. A precursor to carbonization of membrane II (organic-inorganic composite) was formed in the pores of unmodified membranes from liquid glass and the polyisocyanate a...

Ultrafiltration membranes were obtained by means of modification of microfiltration ceramic membranes with pyrocarbon from polyisocyanate and sodium carboxymethyl cellulose. For Ca²⁺ the retention factor and the specific productivity of the modified membranes depend on their composition and filtration time of the solution being purified and vary fr...

The sorption of functional molecules is a simple rather effective way of modification of nanostructures. The goal of this work is to study the sorption of various polymethine dyes on nanographites and carbon nanotubes. A simple technique affording the preparation of macroscopic amounts (tens of grams) of nanographite from an available starting mate...

Modification of ceramic membranes was conducted with silica, obtained from liquid glass, and pyrocarbon from carbonized polyisocyanate and sucrose at 800°C. Water from Ca²⁺ and direct scarlet dye was purified by a pressure-driven method at 0.7 and 1.1–1.2 MPa. The retention coefficient of Ca²⁺ and specific productivity of the modified membranes dep...

Synthesis of preparative amounts of stable dispersions of graphite, partially oxidized graphite, and oxidized graphite modified with ethylenediamine nanostructures in organic solvents (ethanol and dioxane) is worked through. The interaction of polymethine (anionic and cationic) dyes with different types of carbon nanostructures in ethanol solutions...

Cellulose acetate and polyisocyanate copolymer synthesized by simultaneous mixing of cellulose acetate and polyisocyanate with acetone solution of Copper chloride and fumed silicon dioxide was carbonized in a silicon dioxide template. The composite structure and composition was studied with SEM, EDS and XRD. It was shown that the porous carbonaceou...

Cellulose acetate and polyisocyanate copolymer synthesized by mechanical mixing of cellulose acetate, polyisocyanate and fumed silicon dioxide in the presence of nickel chloride was carbonized in silicon dioxide template. Copolymer and silicon dioxide template were formed simultaneously. Composite structure and composition was studied with SEM and...

Modification of membranes by pyrocarbon was carried out by carbonization of polyisocyanate, celluloacetate and Na-salt of carboxylmethyl cellulose at 750°C. The water was purified of dyes by the pressure-driven method under pressure from 0.1 to 1.1 MPa. The retention coefficient and specific capacity of modified membranes for direct scarlet vary re...

Pyrocarbon modification of microfiltration ceramic membrane from aluminum oxide by carbonization of polyisocyanate has been carried out. The structure of pyrocarbon was regulated by means of water, glycerin and nickel chloride. Water of purified of dyes by pressure-driven method at the pressure in the range 0.5–1.1 MPa. The retention coefficient an...

Impact of few-layered graphene (FLG) plates on the properties of the ED- 20 epoxy resin is experimentally studied by using various techniques. The average dimensions of FLG plates are estimated as about 50 nm in thickness and 5 μm in both width and length. The FLG-mass-loading, Cf, in the nanocomposites is ranged from 0.01% to 5%. On the whole, the...

Using the method of low-temperature 1H NMR-spectroscopy we investigated isotope effects in adsorption of water and hydrochloric acid by the surface of nanosilica A-300 and in particular dehydrated cells Saccharomyces cerevisiae. It is shown that replacement of protium by deuterium results in the growth of the amount of water bound with silica. Solu...

The article has considered physical and crystallographic properties of substances, which expand in crystallization. It has also proposed explanation of manifestation of these properties in the formation of the crystalline lattice of a special type—hexagonal, cubic or tetrahedral with corresponding changes of the length and angles of interatomic and...

Exfoliated graphite (EG) has been modified with pyrolytic carbon produced by 750°C carbonization of poly(vinylidene fluoride) (PVDF), tolylene diisocyanate (TDI), and polyisocyanate (PIC) applied to the EG surface from solutions. The pyrolytic carbon obtained had the form of particles ranging in size from 200 nm to 1 μm. The microstructural charact...

The article has shown the prospects of using in practice of treating water systems of electrodes-charge methods being one of the priority areas in the field electroenvironmentally friendly technologies thanks to the bactericidal effect and the absence of a need in chemical reagents. The article has determined the necessity of the differential appro...

In the present work, we report for the first time one-pot synthesis of carbon nanotubes (CNTs) by pyrolysis of cellulose acetate (CA) cross-linked with polyisocyanate in the fumed silica template. NiCl2 was chosen as precatalyst for CNT growth. The diameter of CNTs is 24–38 nm and their wall thickness is 9–11 nm. The main role in the formation of C...

Ni/C/SiO2 porous composites were synthesized by one-pot approach by carbonization of sodium carboxymethyl cellulose/SiO2 xerogels containing NiCl2. Synthesized composites are mesoporous materials (average pore size 11.8 -15.1 nm) with the surface area 72.1-91.1 m 2/g. Ni nanoparticles of 30-90 nm in diameter are evenly distributed within the volume...

The solute-solvent and solvent-solvent interactions govern the structure of liquid solutions. Vice versa, the structure of liquid solutions affects the solute-solvent interactions. The microstructure of solvent medium surrounding the solute molecule depends on its electronic state. This work studies the solvent-induced spectral shifts of benzene (B...

Results of studies of the electronic structure of carbon-containing porous materials derived by tolylene-diisocyanate (TDI) carbonization in a matrix of Al2O3 are presented in this paper. It has been established that products of TDI carbonization are fine spherical clusters (with their sizes of about 10 nm) that reveal a strong bonding with the mat...

The destruction ability of SnCl4, TiCl4, CCl 4 and the sedimentation of metallic and carbon structures on their base on the interface because of interaction between the near optical field of subwavelength-diameter tapered optical fibres and a matter are demonstrated. The fields' distribution within the sub-wavelength fibre lightguides is analyzed....

Using poly(vinylidene fluoride) (PVDF) carbonization at 750° C in fine-particle silica and its mixtures with graphite, we have prepared carbon-loaded porous composites which offer benzene absorption from 0.90 to 1.52 ml/g, compressive strength of 6 MPa, and Brinell hardness of up to 18 MPa. We observed the formation of various nanostructures (spher...

The electronic structure of products of carbonization of polyvinylidene fluoride (PVDF) on SiO 2 nanoparticles was studied using the X-ray emission and photoelectron spectroscopy methods. The shape of the X-ray emission СKα band of products of carbonization of PVDF in a SiO 2 matrix resembles that of the band of fullerene C 60 containing other carb...

Two new technologies were developed for manufacturing of novel carbon nanomaterials (fullerenes, nanotubes, carbonic nanoclusters) based on the idea of high-energy plasmochemistry synthesis, using the methods of electrical wire explosion and spark erosion of graphite and metallic materials (nickel, iron, copper) in an organic medium. A wide spectru...

Microporous materials were obtained by pyrocarbon modification of matrices based on a highly dispersed silicon dioxide. The modification involved polystyrene carbonization at 400 and 700°C in an argon flow. The possibility was elucidated of varying the properties of porous materials (density, porosity, sorption of organic solvents, and compression...

The paper presents results of theoretical and experimental investigations of the process of electrochemical conversion of organic dielectrics into nanosized carbon structures. A new low-temperature method for the synthesis of fractal carbon materials with micro- and nanoparticles having a fibrous, spheroidal, dendritic, and other structure has been...

Carbon nanostructures were prepared by the carbonization of polystyrene, which was introduced as solutions into fumed silica based composites-matrices. Composite-matrices were impregnated with polystyrene solutions, or the latter were used as a dispersion medium at the stage of forming the composite-matrix. The precursor was carbonized at 750 °C in...

There were developed two new technologies for manufacturinzg of novel carbon nanomaterials (fullerenes, nanotubes, carbonic nanoclusters) based on the idea of high-energy plasmochemistry synthesis with the use of the techniques of electrical wire explosion and spark erosion of graphite and metallic materials (nickel, iron, copper) in organic medium...

We have studied the influence of surface state of aerosil on electro-optical characteristics of suspensions ‘aerosil-liquid crystal (LC)’. Modification of aerosil surface by hydrophobic fragments improves these characteristics. Also the dependence of a hydrophobic modificator structure on electro-optical characteristics was investigated. Explanatio...

Carbon-loaded porous materials have been produced by modifying inorganic matrices with pyrolytic carbon prepared via polystyrene carbonization at 750C in an argon atmosphere. The matrices have been produced from silica particles about 80 nm in size, and polystyrene has been introduced either via impregnation or using polystyrene solutions as disper...

Research work in Russian language. Contract No. 63/06-H.

Products of electrical explosion and electrical erosion of graphite, nickel, and iron in organic medium are tested by X-ray diffraction, electron microscopy, and mass-spectroscopy. A wide spectrum of fullerene-like materials including the highest ones (C70 and higher) is obtained and studied. Ferromagnetic properties of carbon nanomaterials are det...

A method for production of porous composites from pyrogenic silicas, whose surface is preliminarily modified with methyl and trimethyl siloxane groups, was developed. In order to diminish shrinkage, glass microspheres and organosilicon compounds were used as modifiers. The total porosity of the composites obtained was 0.28 – 0.55.

Using the method of quasi-elastic scattering of slow neutrons, the influence of the contact between distilled water and a hydrophobic surface (porous silica covered with trimethylsilane) on self-diffusion of water molecules has been studied. It has been established that after the contact of water with the hydrophobic surface the self-diffusion cons...

Thermal stability of organosilicon nanoclusters on high-disperse silica surface of varied degree of dimethyl- or trimethylsilylation was studied by means of IR spectroscopy and thermal analysis methods. The technique allowing to control the degree of surface hydrophobicity via variation of temperature and/or time of thermal treatment of extremely h...

The peculiarities of the preparation of carbon nanostructures in different states of aggregation have been briefly characterized. The methods of physico-inorganic chemistry such as plasmochemical and electrochemical synthesis, carbonization of adsorbed substances in pores of an inorganic composite matrix were used. The possibilities of the synthesi...

The pyrolytic gas-phase carbon deposition upon thermal decomposition of methylene chloride vapor on the surface of a mesoporous silica MCM-41. The formation of nanotubes, nanofibers, and amorphous carbon particles was observed depending on pyrolysis conditions.

To concentrate and separate carbon nanostructures, coatings from synthesized composite materials based on the pyrogenic nonporous silica and ethanol as a dispersion medium and polydimethylsiloxane modifier have been employed. It has been found that the concentration of solutes from solution occurred in thin layers of coatings.

The effects of 60Co γ-radiation, 75-keV electrons, and thermal history (295–973 K) on the surface properties of pyrogenic γ-Al2O3 were studied by thermal desorption mass spectrometry. It was found that the state of a hydroxyl cover and the concentrations of surface acid–base sites and chlorine impurity atoms can be regulated by changing the conditi...

Cu- and Eu-doped Li2B4O7 has been characterized using steady-state and time-resolved photoluminescence, radioluminescence and optical absorption techniques. The effect of dopant content (7.0×10−4–5.0×10−2 wt% for Cu and 1.6×10−3–8.0×10−3 wt% for Eu) and of host modification (single crystal, polycrystalline and glassy) has been investigated.

Special features of high-temperature transformations on the surface of dimethyl- and trimethylsilylated silica with various degrees of hydroxyl groups substitution were investigated by the method of thermoprogrammed desorption mass spectrometry. The results of mathematical treatment of 16 and 27 m/z thermograms caused by methane and ethylene evolut...

Conditions of synthesis of carbon nanotubes by pyrolysis of dichloromethane on Al2O3 membranes were studied. The special features of nanotubes morphology were determined. The nature of functional groups on the surface of carbon nanotubes was studied by IR- and X-ray photoelectron spectroscopy.

Current considerable application of atomic energy along with the Chornobyl Shelter problems makes the ecology of the nuclear energy of great importance in Ukraine. Therefore the elaboration of advanced dosimetric materials for radiation monitoring in the wide energy of ionizing radiation (IR) and dose ranges is highly requested. During last years w...

Composite materials (CM) based on poly(ethylene) (PE) and nanocrystalline nickel (Ni) have been produced. The effect of the content of nanocrystalline Ni and processes of structure formation of its particles on a melting temperature (T m), interval of melting, true melting heat (ΔH m), degree of crystallinity (χ) as well as characteristics of CM th...

The solid-phase decomposition of the iron formate crystal hydrate Fe(HCOO)2 2H2O under exposure to 60Co -rays or 3.5-MeV electrons was studied. It was found that the irradiation of this salt to absorbed doses of 0.1–2 MGy resulted in the radiolysis of water of crystallization and the HCOO– anion and in the reduction or oxidation of the Fe2+ cation....

N-Containing carbon nanotubes were prepared by the pyrolysis of acetonitrile in an alumina matrix. Nanotubes were obtained with given diameter and length. Amorphous carbon is also formed on the alumina surface in the acetonitrile pyrolysis.

The results of investigation of the processes occurring on the surface of three-dimensional electrode of thermoexpanded graphite by its cathodic polarization in low-concentrates aqueous solutions are presented. It is shown that oxygen-containing functional groups located at the surface of thermoexpanded graphite affect the process of nickel electro...

In the YBa2Cu3O7−δ superconductor, the excitation of slightly damped plasmons upon the nonuniform heating of electron gas in a microwave electromagnetic field and upon perturbation of the charge density by the thermal desorption of oxygen atoms from the Cu1-O plane suppresses surface and volume diffusion of nickel and gold interstitials. The inters...