Use of by-product coke phenols as thermal polymerization inhibitors in processing of pyrolysis intermediates

A new procedure was suggested for modification of by-product coke phenols with the aim to eliminate drawbacks revealed in the course of their long-term use as inhibitors of thermal polymerization of unsaturated pyrocondensate components, namely, low inhibiting activity, high water solubility, and unpleasant odor. These drawbacks are eliminated by phenol formaldehyde polycondensation of total phenols, similar to Novolac production. Original Russian Text ? A.F. Gogotov, A.V. Turova, O.I. Baranov, I.I., Batura, E.V. Puchenin, V.K. Stankevich, A.A. Levchuk, A.A. Gulyaeva, D.V. Gendin, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 9, pp. 1573–1574.     

States of atoms and interatomic interactions in perovskite-like oxides: XXI. Effect of dopant nature on the magnetic properties of lanthanum manganites x (La1? y Y y )0.67Ca0.33MnO3-(1? x )La1? y Y y AlO3

A procedure of sol-gel synthesis was developed and solid solutions of lanthanum manganites doped with calcium and yttrium, containing 10 and 20% of yttrium, were obtained. The temperature and concentration dependences of the magnetic characteristics of the solid solutions were examined to reveal exchange interactions in the doped manganites and reasons for their different magnetic behavior. The properties of yttrium-substituted manganites vary nonmonotonically with increasing concentration of yttrium. Original Russian Text ? N.V. Chezhina. A.V. Fedorova, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 5, pp. 705–709. For communication XX, see [1].     

The Use of a Solid Bismuth Microelectrode for Vanadium Quantification by Adsorptive Stripping Voltammetry in Environmental Water Samples

This paper presents for the first time the use of an environmentally friendly solid bismuth microelectrode for the voltammetric quantification of V(V) in natural water samples. These studies were designed to replace the film bismuth electrode that had been introduced to eliminate the conventional sensors based on highly toxic mercury. In the proposed procedure, V(V) is preconcentrated at the solid bismuth microelectrode surface via the formation of electroactive complexes with cupferron from a solution of 0.1-mol L⁻¹ acetate buffer, pH = 4.6 at a potential of −0.4 V. The linearity of the calibration graph is in the V(V) concentration range from 8 × 10⁻¹⁰ to 1 × 10⁻⁷ mol L⁻¹ with a preconcentration time of 1 min. The limit of detection (calculated as 3 σ) is 2.5 × 10⁻¹⁰ mol L⁻¹ for a preconcentration time of 1 min. It was also demonstrated that significant improvement in analytical parameters was achieved as a result of the activation of the solid electrode surface at a potential of −2.5 V for 2 s. The developed procedure is highly selective for the presence of foreign ions and organic compounds in tested samples. The accuracy of the recommended procedure was checked using SPS-WW1 waste water-certified reference materials of a complex composition, in which the concentration of V(V) determined by the proposed method was 95.1 ± 1.6 ng mL⁻¹. Moreover, in keeping with the outlined procedure, river, tap and rain water samples were analyzed without any pretreatment, and recovery values from 96% to 106% were obtained.     

High performance liquid chromatography hydride generation in situ trapping graphite furnace atomic absorption spectrometry: A new way of performing speciation analysis using GFAAS as detector

A new procedure for the speciation analysis of hydride forming elements using GFAAS as detector is proposed. The separation of the species is performed by HPLC and the eluent flow is merged with HCl and NaBH₄ solutions moved by peristaltic pumps controlled by a flow injection apparatus. As the species emerges from the column, its respective hydride is formed and carried through the autosampler capillary to an Ir treated graphite tube pre-heated at 300 °C, where it is trapped. After the hydride collection, the autosampler arm is moved from the tube and atomization takes place. The sequence is repeated for the next emerging species. The feasibility of the system was evaluated for the speciation of As (III) and As (V) in waste water samples. The retention times were previously determined using a more concentrated mixed analytical solution and a quartz tube as atomizer. The analytical curves obtained by the proposed procedure showed similar slopes for both species as well as coefficient of regression better than 0.99. Limits of detection were 0.2 ng/mL for both species, 50 times better then the same assembly using a quartz tube atomizer. In the analysis of certified reference materials the sum of the As (III) and As (V) species concentrations were in close agreement with the arsenic concentration certified for total arsenic.     

Kinetics of photolytic transformations of 4,4′-Bi(3-methyl-6-<Emphasis Type="Italic">tert</Emphasis>-butyl-<Emphasis Type="Italic">o</Emphasis>-benzoquinone)

The quantum yields and apparant rate constants of the photolysis of 4,4′-bi(3-methyl-6-tert-butyl-o-benzoquinone) and of accumulation of its transformation products in hydrocarbon solutions under the action of light with λ 313 and 405 nm were determined. The probable scheme of photochemical reactions was suggested. Original Russian Text O.G. Mishchenko, S.V. Maslennikov, I.V. Spirina, N.O. Druzhkov, Yu.A. Kurskii, V.P. Maslennikov, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 12, pp. 1997–2001.     

Vanadium(V)-doped MCM-41 synthesised by a novel one-step procedure

 A novel procedure to synthesise V-doped surfactant–templated mesoporous materials in one step using a V(V) complex is described. The resulting V(V)–MCM-41 material had a bimodal pore size distribution. Received: 25 April 2001 Accepted: 20 June 2001     

Adsorptive Cathodic Stripping Voltammetric Method for Determination of Gallium Using an In Situ Plated Lead Film Electrode

The in situ plated lead film electrode was proposed for the first time for adsorptive stripping voltammetric determination of gallium in water samples. The method was based on simultaneous lead film formation and Ga(III)‐cupferron complex preconcentration at ?0.7 V and its cathodic stripping during the potential scan. The composition of the supporting electrolyte, cupferron concentration, conditions of lead film formation, potential and time of accumulation were studied in detail. Under optimum conditions the limit of detection was 3.8×10^?9 mol L^?1. The proposed procedure was validated in the course of Ga(III) determination in waste water certified reference materials.     

Studies of leaching of copper ores and flotation wastes

In Poland, there are significant deposits of copper ores. During the copper extraction, large amounts of flotation wastes are produced. In the ores and flotation wastes many other important elements are present. The main goal of this work was analysis of uranium content and to elaborate procedures for recovery of U from these materials. Two types of ores and four types of waste were examined. It has been found that uranium content varies from 4.5 to 25 ppm. The other elements have also been determined in these materials: Cu (4–5 % in ores and 0.3–1.7 % in waste), Ag, Re, Mo, La, Ni, V, etc. For leaching, sulfuric acid and sodium carbonates of various concentrations (temperature, time) were used. The optimum conditions for leaching have been found. The concentration of uranium in the final solution was generally less than 25 μg/mL. The other elements are also present in the leaching solutions. Simultaneous liquid–liquid extraction of uranium with these elements from leaching solution is under study. In our opinion, only such combined procedure for the recovery of uranium together with the accompanying elements could be cost-effective.     

Spectrophotometric determination of chromium with diphenylcarbazide in the presence of vanadium, molybdenum, and iron after separation by solid-phase extraction

A method has been developed for the determination of chromium in presence of V(V), Mo(VI), and Fe(III). The effects of interferences were evaluated by using the apparent content curves method, and their separation was performed by solid-phase extraction with an anionic exchanger. The sample-treatment conditions and the influence of the sample conductivity were studied. Tolerance limits were established, and the proposed procedure was used to determine chromium in certified samples and for speciation of chromium in waste water. Our results were always in agreement with the theoretical content.     

Formation of superhydrophobic surfaces by the deposition of coatings from supercritical carbon dioxide

The deposition of uniform coatings of fluorinated polymers from solutions in supercritical carbon dioxide on a number of rough substrates allowed superhydrophobic (ultrahydrophobic) properties to be imparted to their surfaces, and, namely, to increase the value of the contact angle for water droplet to 150° and greater. The dynamics of changing of geometry of a drying droplet on a substrate is studied. A procedure is developed that permits the penetration of water into the substrate to be detected. Original Russian Text & M.O. Gallyamov, L.N. Nikitin, A.Yu. Nikolaev, A.N. Obraztsov, V.M. Bouznik, A.R. Khokhlov, 2007, published in Kolloidnyi Zhurnal, 2007, Vol. 69, No. 4, pp. 448–462.     

A road map to assess critical materials content in boron industrial wastes using sustainable micro-X-ray fluorescence and total reflection X-ray fluorescence instrumentation

Turkey is the leading country in the world in terms of boron production and sale. Increasing boron production goes along with an increasing generation of boron wastes. The pollution of the soil and the air around the waste piles, as well as the occupation of several square kilometers of ground, are major environmental problems. It is, therefore, very important to make use of the wastes to both protect the environment and create revenue. This work presenteda road map for fast screening of boron waste for critical elements followed by determination of the elements using small footprint low power instrumentation. The sample preparation was kept to a minimum. A procedure that allowed an assessment of critical materials in industrial production waste with minimal consumption of hazardous acids, energy, and time was presented. The samples were first screened for valuable and hazardous elements by micro-X-ray fluorescence (XRF). Samples with considerable contents of Cs, Rb, and Aswere then prepared as slurries for the total reflection XRF (TXRF) measurement. To evaluate the TXRF procedure, a standard reference material was analyzed. As a result, Rb and Cs in concentrations up to 420 ± 70 and 1500 ± 200 mg/kg were detected in some of the waste forms. The time savings were in order of a factor of 3 when comparing the prescreening combined micro-XRF and TXRF approach to an all TXRFanalysis approach.     

Extraction and Stripping Behavior of U-Np-Tc Ternary System to TBP

In order to remove U, Tc, and Np, which are positioning materials or target nuclides for transmutation, from the high-level radioactive waste, condition of co-extraction and sequential and sequential stripping of the nuclides wer studied by using 30 vol.% TBP. On the basis of the experiments ferformed on each element of U, Tc, and Np, a combination of co-extraction of U, Tc, Np Tc stripping Np stripping U stripping was suggested. To enhance the Np extraction yield, the electrolytic exidation of Np(V) was required at the co-extraction step. For the stripping of Tc 5M HNO₃, of Np the electrolytic reduction of Np(VI) to Np(V), and of U 0.3M sodium carbonate were used. Phase ratios (O/A or A/O) were recommended to be of 2-3, for co-extraction and for stripping.     

Polyaniline-polypyrrole coating for solid phase microextraction

A procedure for direct electrochemical deposition of polyaniline-polypyrrole blend coating on the surface of stainless steel wire was suggested. Incorporation of polyaniline and polypyrrole into the blend coating was confirmed by infrared spectroscopy. Key parameters (pyrrole, aniline, dopant and sulphuric acid concentrations and deposition potential) influencing the coating’s mechanical stability and surface homogeneity were optimised and thermostability of the coating was investigated. A possibility to apply the coating as a new fibre for solid phase microextraction was demonstrated. The coating showed better selectivity toward aromatic, hydrophobic compounds.      

Reduction of arsenic trichloride with hydrogen

The composition of an equilibrium vapor-gas mixture in the range 700–1100 K was estimated for the reaction of arsenic trichloride with hydrogen taken in excess of a = 1.0–2.5 as compared to the stoichiometry. The temperatures of the onset of arsenic condensation (dew point) were found. Kinetic parameters of the chemical reaction were determined. Optimal conditions for the reduction of arsenic trichloride with hydrogen were refined and conditions for the condensation of arsenic with the minimum fraction of the amorphous modification were found. Original Russian Text ? N.A. Potolokov, A.V. Serov, V.N. Potolokov, A.V. Zhuravlev, V.P. Kolganov, E.G. Zhukov, V.A. Fedorov, V.I. Kholstov, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 1, pp. 3–8.     

Arsenic solubility, mobility and speciation in the deposits from a copper production waste storage

The sediments in large pond for discharge of waste products of metallurgical activity were studied with respect to the valence forms of arsenic and its mobility. A sequential extraction procedure for arsenic compounds was applied and optimized according to the nature of analyzed products. During the first stage, the content of water-soluble arsenic compounds was determined, during the second—HCl-soluble forms and during the third—compounds soluble in sodium hydroxide. The optimum conditions for leaching arsenic from sediments (sample weight, concentration and volume of extractants, time of treatment) were established for each fraction.Speciation studies for determining As(III) and As(V) were carried out in the obtained arsenic extracts. The ability of the proposed sequential extraction procedure to specify the valence forms of inorganic arsenic was evaluated using model samples with added As(III) and As(V) and the recovery of spikes has been assessed. It was found that oxidation of As(III) and processes of sorption and sedimentation of As(V) proceed upon dissolution. A depth profiling was performed of the content of diverse forms of Às in two sites. The content of water-soluble As does not exceed 7.4% of total As in the sediments, As(III) being lower than 7.4% of that of the extracted As. The bulk of arsenic compounds (above 78% As) is dissolved in 2M HCl, and As(V) was found to be more than 94% of extracted arsenic. The analytical features of the procedure are as follow: precision, evaluated through the repeatability w > 0.96 and accuracy, estimated by the recovery above 93%, calculated on the basis of a twice repeated analysis of a series of 9 samples.     

Production of activated carbons from biodegradable waste materials as an alternative way of their utilisation

New carbonaceous adsorbents were prepared by means of direct, physical and chemical activation of corn cobs and cherry stones as well as coffee and tobacco industry waste materials. The effect of activation method on the textural parameters, acid-base character of the surface and sorption properties toward toxic gases of the materials obtained was tested. Depending on the precursor as well as method of preparation, the final products were micro/mesoporous activated carbons of surface area reaching to 1426 m²/g, showing largely different acid-base properties of the surface. The results obtained in our study have proved that a suitable choice of the activation procedure for industrial and agricultural biodegradable waste materials permits production of cheap carbonaceous adsorbents with very high sorption capacity towards nitrogen dioxide and hydrogen sulphide reaching to 83 mg NO₂/g_ads and 215 mg H₂S/g_ads, respectively.     

Determination of vanadium in biological materials at nanogram level by neutron activation analysis

A method for the destructive activation analysis of vanadium in biological samples at the nanogram level has been developed, based on 3.75 min⁵²V. A totally post-irradiation procedure is used, consisting of wet ashing and solvent extraction with N-benzoyl-N-phenylhydroxylamine (BPHA). Time of separation is about 12 min and the radiochemical purity excellent. Possible nuclear interferences were also investigated. The procedure was checked by an alternative method, using preashing and pyrosulfate fusion, and at higher levels, by nondestructive analyses. Results are presented for some 15 standard (or proposed) standard reference materials.     

Physicochemical properties of composite sorption-active materials based on zeolite and fluorinated ethylene derivatives

A procedure was suggested for preparing composite sorption-active materials based on zeolite and fluorinated ethylene polymers. The morphology of these materials, their resistance to mechanical action, and their ability to sorb water vapor under static and dynamic conditions were examined.     

Selectivity assessment of an arsenic sequential extraction procedure for evaluating mobility in mine wastes

An optimized sequential extraction (SE) scheme for mine waste materials has been developed and tested for As partitioning over a range of pure As-bearing mineral phases, their model mixtures, and natural mine waste materials. This optimized SE procedure employs five extraction steps: (1) nitrogen-purged deionized water, 10 h; (2) 0.01 M NH₄H₂PO₄, 16 h; (3) 0.2 M NH₄-oxalate in the dark, pH3, 2 h; (4) 0.2 M NH₄-oxalate, pH3/80 °C, 4 h; (5) KClO₃/HCl/HNO₃ digestion. Selectivity and specificity tests on natural mine wastes and major pure As-bearing mineral phases showed that these As fractions appear to be primarily associated with: (1) readily soluble; (2) adsorbed; (3) amorphous and poorly-crystalline arsenates, oxides and hydroxosulfates of Fe; (4) well-crystalline arsenates, oxides, and hydroxosulfates of Fe; as well as (5) sulfides and arsenides. The specificity and selectivity of extractants, and the reproducibility of the optimized SE procedure were further verified by artificial model mineral mixtures and different natural mine waste materials. Partitioning data for extraction steps 3, 4, and 5 showed good agreement with those calculated in the model mineral mixtures (<15% difference), as well as that expected in different natural mine waste materials. The sum of the As recovered in the different extractant pools was not significantly different (89–112%) than the results for acid digestion. This suggests that the optimized SE scheme can reliably be employed for As partitioning in mine waste materials.     

Synthesis and N-Alkylation of 2-Alkyl-and 2-Arylimidazole-4,5-dicarboxylic acid esters

Nitration of d-tartaric acid, followed by treatment of the resulting dinitrotartaric acid with ammonia and aldehydes gave 2-phenyl-, 2-(2-pyridyl)-, 2-isopropyl-, and 2-isobutylimidazole-4,5-dicarboxylic acids. Some factors affecting the yield of the final products were revealed, and optimal conditions for their esterification were found. N-Alkylation of 2-substituted imidazole-4,5-dicarboxylates thus obtained involves considerable steric hindrances; therefore, the corresponding N-alkyl derivatives can be obtained in a poor yield only in the presence of such a strong base as 1,8-diazabicyclo[5.4.0]undec-7-ene. Original Russian Text A.V. Lebedev, A.B. Lebedeva, V.D. Sheludyakov, E.A. Kovaleva, O.L. Ustinova, V.V. Shatunov, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 5, pp. 855–859.