Estimating the Minimum Pore Size in Globular Systems with Capillary Hysteresis

Yu. K. Tovbin and A. G. Petukhov

Karpov Institute of Physical Chemistry, ul Vorontsovo Pole 10, Moscow, 105064 Russia

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Received June 15, 2007

Abstract — A technique of estimating the minimum size of pores in regular globular structures, the isotherms of which may have a hysteresis loop that indicates the capillary condensation, is proposed. As a criterion of the minimum pore size, the contribution from the middle pore volume unaffected by the wall potential, which was found from the experimental data for infinitely long cylindrical channels, is used. The estimates for regular globular structures are compared to the similar estimates for spherical and cubic pores. The ways of taking into account the restricted size of pores in the case of irregular globular packing are discussed.

PACS numbers: 47.55.nb

Molecular Statistics Calculations of Thermodynamic Characteristics of the Adsorption of Isomeric Amino Acids on Graphitized Thermal Black

E. S. Kuznetsova, A. V. Ul’yanov, and A. K. Buryak

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

Received June 26, 2007

Abstract — Thermodynamic characteristics of the adsorption of several isomeric amino acids on graphitized thermal black (GTB) are calculated by a molecular statistics method. Parameters of the potential function of the intermolecular pair interaction between an O atom of amino acid and a C atom of graphite are calculated.

PACS numbers: 68.43.De

Adsorption of Inhibitors Based on Vegetable Raw Materials at Steel

O. I. Sizaya, O. N. Savchenko, A. A. Korolev, and V. G. Ushakov

Chernigov State Technological University, ul. Shevchenko 95, Chernigov, 14027 Ukraine

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Received April 3, 2007

Abstract — The adsorption mechanism of corrosion inhibitors prepared from the modified vegetable oil (MGChDTU and MGS) and the water-soluble fraction of vegetable product wastes (FES) was studied. It was found that the inhibitors both chemisorb and physically adsorb at steel to form polymolecular protective layers.

PACS numbers: 82.45.B

Electrochemical Synthesis of Ultradispersed Copper-Containing Powders Obtained from Solutions of Copper Nitrates in Aqueous Propan-2-ol

V. I. Parfenyuk*,** and M. V. Tesakova*

* Institute of Chemistry of Solutions, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia

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** Ivanovo State University of Chemical Technology, pr. F. Engel’sa 7, Ivanovo, 153000 Russia

Received October 25, 2006

Abstract — Nanosized copper-containing powders were obtained by electrochemical synthesis in aqueous organic solutions of electrolytes. The size and shape of the resulting particles were determined by TEM. It was found that the electrochemical crystallization of copper-containing deposits is substantially influenced by the solvent nature. Adding an organic solvent to the electrolyte increased the dispersivity of the powders. A quali-tative analysis of the compounds obtained was carried out by electron diffraction analysis.

PACS numbers: 81.07.Wx, 82.45.Qr

The Mechanism of Formation of Thin Oxide Coatings and Nanopowders at the Anodic Oxidation of Zirconium in Molten Salts

L. A. Elshina, V. Ya. Kudyakov, V. B. Malkov, N. G. Molchanov, and B. D. Antonov

Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, Ekaterinburg, Russia

Received February 16, 2007

Abstract — At the oxidation of zirconium in molten salts up to 813–1073 K, the growth of oxide phases is found to proceed chiefly due to the diffusion of oxygen ions via the oxide film toward the metal–oxide interface. An oxide film formed in the initial period of zirconium oxidation in a chloride–nitrate melt decelerates the process but does not prevent the ion exchange at the metal–melt boundary. As the oxide formation proceeds and the steady-state conditions of the corrosion process are reached, the oxidation rate becomes limited by the diffusion of oxygen ions from the film surface deep into the metal. Along with the diffusion of O² ions at temperatures of 813 to 1073 K, zirconium ions can also migrate in the metal, which makes interpreting the whole process much more difficult. At the oxidation, the films of various colors (from black to light gray) with diverse corrosion and protective properties, as well as fine-dispersed powder of zirconium dioxide with a mean size of particles up to 30 nm, are formed.

PACS numbers: 81.07Wx, 82.45.Qr

Multiphase Anodic Layers and Prospects of Their Application

V. S. Rudnev

Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia

Received November 1, 2006

Abstract—Information on preparing multiphase layers on valve metals by the plasma-electrochemical oxidation and deposition from aqueous electrolytes containing polyphosphate and fluoride metal complexes, iso- and heteropolyoxoanions, as well as electrolytes evolving solid precipitates, is summarized. Possible application fields of the metal/multiphase PEOD surface structure compositions are considered.

PACS numbers: 82.45.Cc, 81.15.Pg

Study of Heteroligand Complex Compounds of Metals with Citric Acid and o-Nitrobenzoylhydrazinein Aqueous Solutions

G. V. Tsintsadze, N. B. Zhorzholiani, I. A. Beshkenadze, and M. A. Gogaladze

YuLPP P. Melikishvili Institute of Physical and Organic Chemistry, ul. Dzhikiya 5, Tbilisi 86, 0186 Georgia

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Received October 10, 2007

PACS numbers: 82.60.Hc, 82.80.-d

Adsorption Characteristics of Nanoporous Montmorillonite Activated with Orthophosphoric Acid

L. I. Bel’chinskaya*, K. A. Kozlov*, S. S. Chitechan*, A. V. Bondarenko**,
G. A. Petukhova***, and M. L. Gubkina***

* Voronezh State Wood Technology Academy, ul Timiryazeva 8, Voronezh, 394613 Russia

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** Lipetsk State Technical University, ul. Moskovskaya 30, Lipetsk, 398600 Russia

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*** Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow,
119991 Russia

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Received June 7, 2007

Abstract — A comparative effect of the preliminary treatment of lamellar silicate with sulfuric and orthophosphoric acids on the subsequent phenol sorption is carried out. Mechanisms of the phenol adsorption on specimens treated with different acid solutions are found to be different. It is shown that orthophosphoric acid is preferable as an activator of montmorillonite, which can then be used in biochemical decontamination of the sewage of by-product coke industry.

PACS numbers: 68.43.–h

Effect of Alcohol on the Corrosion of Al Alloys¹ in 1 N H₂SO₄ Solution Part I

A. Buyuksagis^a and A. A. Aksut^b

^a Afyon Kocatepe University, Science and Art Faculty, Afyon,Turkey

^b Ankara University Science Faculty, Ankara, Turkey

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Received March 12, 2007

Abstract — The aim of this paper is to examine the effects of alcohol (1-buten–3-ol-l, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5-hexen–1-ol) on the corrosion of Alalloys. The inhibiting effect of alcohol was investigated by electrochemical current-potential curves, atomic absorption spectrometry (AAS), metal microscopy,SEM and EDS. The results showed that alcohol (1-buten–3-ol, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5hexen–1-ol) had an inhibiting effect on the corrosion of aluminium alloys. Experimental results show that corrosion of alloys in H₂SO₄ solution have been effected by elements in alloys such as Cu, Zn, Mg and adsorp-tion of alcohol on the surface of alloys in H₂SO₄ solution obeys Temkin adsorption isotherm. The use of alcohol in H₂SO₄ solution were shifted corrosion potentials (E_cor) to more negative values and acted as cathodic inhibitors on the aluminum alloys. EDS analysis of alloys displayed different intermetallic compounds on the surface of alloys, which might have changed the activity of alcohols depending on the surface morphology of alloys. This paper has showed that these alcohol inhibited corrosion of aluminium alloys in H₂SO₄ solution. The concentration of 20 mM alcohol was shown that above 90% inhibition was achieved, which is a rather high value.

PACS numbers: 81.65.Kn

Corrosion Prognosis for Metals with Oxygen Depolarizatio

B. B. Chernov, O. P. Kovalev, and A. V. Volkov

Nevel’skii State Sea University, ul. Verkhneportova 50A, Vladivostok, 690059 Russia

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Received July 20, 2006

Abstract — Based on the results of corrosion tests, the penetration coefficients of corrosion products and the steady-state corrosion rate of an CT-3 steel are statistically assessed as a function of the oxygen concentration distribution.

PACS numbers: 82.45.Bb