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1
Content available remote

Green Synthesis of Pd Nanoparticles via Gallic Acid

100%
Can M.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 3
569-570
EN
A facile, eco-friendly, room-temperature method for rapid one-pot synthesis of Pd metallic nanoparticles has been developed based on the successive reduction of Pd(II) precursors with gallic acid in an aqueous environment. The morphology and surface analysis of the resulting Pd nanoparticles were confirmed by aberration corrected scanning transmission electron microscopy followed by X-ray photoelectron spectroscopy. The particle size of palladium nanoparticles was calculated as 16 nm. This study demonstrates that the synthesis of nanoparticles (reduction and stabilization) can be effectively achieved using gallic acid.
2
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Studies of the Kinetics for Rhodium Adsorption onto Gallic Acid Derived Polymer: the Application of Nonlinear Regression Analysis

100%
Can M.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1308-1310
EN
The kinetic behaviors of solute adsorption at solid/solution interfaces of rhodium (III) complexes from chloride solutions (1 M HCl) onto gallic acid formaldehyde resol polymer were studied by batch mode. Kinetics was analyzed by the pseudo first-order, the pseudo second-order, the Elovich and the intraparticle diffusion kinetic equations using nonlinear regression analysis. The rate constants of four models were calculated. The Non-linear Chi-square analysis and correlation coefficients have been calculated in order to assess which model provides the best fitting predicted data with experimental results. The pseudo second-order equation provides the best fit to experimental data. The first initial kinetics is governed by the rate of surface reaction. When the adsorbed amount reaches about 95% of the equilibrium coverage in the first sixty minutes, it switches to another kinetics governed by the rate of intraparticle diffusion. The proposed adsorption of the aquachlororhodium (III) species mostly takes place via a ligand exchange mechanism.
3
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Rhodium Adsorption on Gallic Acid Resol Resin

100%
Can M.
Acta Physica Polonica A
|
2015
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vol. 127
|
issue 4
1301-1307
EN
A new adsorbent resin has been developed by immobilizing gallic acid with formaldehyde, and its adsorption properties to Rh^{3+} were reviewed with respect to the collection in aqueous solution. Linear and nonlinear regression procedures have been applied to the Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich, and Redlich-Peterson isotherms. The resin exhibited good adsorption capacity towards Rh^{3+} from acidic aqueous solutions ([H^{+}]=1 M, [Cl^{-}]=1 M). The equilibrium adsorption capacity at 293 K was up to 69.43 mg g^{-1}. The adsorption isotherms could be well described by Langmiur equation. The experimental studies suggested that gallic acid formaldehyde resin was effective for the adsorption of Rh^{3+} from chloride acid solutions, and the loaded Rh^{3+} could be easily desorbed from the 1 M HNO₃ + 0.1 M NaClO₃ solution mixture with a hundred percent efficiency. Thermodynamic parameters such as the entropy change, enthalpy change and Gibbs free energy change were calculated. The adsorption of Rh^{3+} was found to be an endothermic adsorption process. This suggested that the resin can be used as an active biosorbent for the recovery of Rh^{3+} from 1 M HCl concentrated acid solution.
4
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Study on Species of Heavy Lanthanides(III) Chelates Extracted into Organic Phase with 5,7-Dichloro-8-hydroxyquinoline

63%
Czakis-Sulikowska D., Malinowska A., Pustelnik N., Kuźnik B.
Acta Physica Polonica A
|
1996
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vol. 90
|
issue 2
427-430
EN
The nature of species formed in the extraction of lanthanides Ln(III) (where Ln = Tb, Dy, Ho, Er, Tm and Yb) with 5,7-dichloro-8-hydro xyquinoline (HL) in CHCl_{3} from water or water-methanol phase was examined. It was stated that during the extraction from water phase the chelates LnL_{3} (Tb, Tm), seven-coordinated self-adducts LnL_{3} ÷ HL (Er, Ho) or both types of these species (Dy, Yb) were extracted. In the presence of methanol (MeOH) in the aqueous phase the eight-coordinated mixed species of the type LnL_{3}·2MeOH were observed.
5
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Structure and Catalytic Properties of Co-Fe Systems in the Reaction of CO₂ Methanation

51%
Zhludenko M., Dyachenko A., Bieda O., Gaidai S., Filonenko M., Ischenko O.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 4
1084-1087
EN
The properties of Fe-Co catalysts in the reaction of CO₂ hydrogenation were investigated. Samples with high cobalt concentrations have shown higher activity. Morphology of the obtained catalysts was observed by using scanning electron microscopy and the elemental composition of surface of the catalysts was determined by scanning electron microscopy-energy dispersive X-ray method. Energy dispersive X-ray analysis showed that metal distribution is not homogeneous with various metal ratio in selected points of the surface for the Fe-rich less active samples, whereas for the Co-rich samples with higher activity metals are homogeneously distributed, which is possibly connected to the formation of single phase.
6
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Catalytic Properties of Ni-Fe Systems in the Reaction of CO₂ Methanation at Atmospheric Pressure

51%
Meshkini-Far R., Dyachenko A., Gaidai S., Bieda O., Filonenko M., Ischenko O.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 4
1088-1090
EN
Catalytic activity, phase composition, and morphology of binary Ni-Fe metallic systems in CO₂ hydrogenation were investigated. High methane yield was detected in the region of high Ni content, except the sample with 75% of Ni which has shown a sharp drop in activity. By means of scanning electron microscopy-energy dispersive X-ray and X-ray diffraction methods the differences in surface structuring of active (Ni₈₀Fe₂₀) and inactive (Ni₇₅Fe₂₅) catalysts were revealed. High methane yield for the former might be explained by defective porous superficial layer of catalyst grains, whereby for the latter the specific surface is diminished due to sintering.
7
Content available remote

Positron Annihilation in Chloropolystyrenes

51%
Baranowski A., Dębowska M., Jerie K., Mirkiewicz G., Rudzińska-Girulska J., Sikorski R.
Acta Physica Polonica A
|
1993
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vol. 83
|
issue 3
239-249
EN
Results of angular correlation of annihilation radiation and positron annihilation lifetime measurements are presented for atactic polystyrene and chloropolystyrenes. The inhibition of positronium formation follows the chlorine introduction as the decrease in intensities of the narrow component in angular correlation of annihilation radiation curves and of the longest-lived component in positron annihilation lifetime spectra prove. In general, the chlorine "activity" towards positrons seems to depend on its position in the polymer structure. The annihilation rate distribution as well as the radius and volume distributions of free-volume sites where positronium is assumed to be formed obtained with the use of CONTIN program for the raw sample in the 2nd series are given additionally.
8
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Liquid Crystalline Polyurethanes Studied by Positron Annihilation Method

51%
Baranowski A., Dębowska M., Jankowski A., Jerie K., Penczek P., Rudzińska-Girulska J., Szczepaniak B., Wolińska-Grabczyk A.
Acta Physica Polonica A
|
1995
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vol. 88
|
issue 1
21-27
EN
A series of liquid crystalline polyurethanes of different both flexible spacer length and mesogenic group content was studied by means of positron annihilation method. The investigated polymers were targeted on the sep­aration of aromatic hydrocarbons from their mixtures with aliphatic ones. The effect of modification of the liquid crystalline polyurethane chain on the polyurethane free volume size and free volume distribution was determined on the basis of the positron annihilation lifetime spectra. In the positron annihilation lifetime spectra measured for the samples under study two long com­ponents of several nanoseconds, characteristic of o-Ps decaying by pick-off, occurred. The correlation of the values of the o-Ps lifetime with the size of the free volume region allowed to recover the free volume distributions with the use of the method employing the numerical Laplace inversion technique. The obtained results were compared with the diffusion data on the mobility of liquid hydrocarbons in the liquid crystalline polyurethanes enabling the correlations between polymer structure and its transport properties to be evaluated.
9
Content available remote

Positron Annihilation Studies of Styrene-N-X-Phenylmaleimides

51%
Baranowski A., Dębowska M., Jerie K., Rudzińska-Girulska J., Pawełka Z., Sikorski R. T.
Acta Physica Polonica A
|
1995
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vol. 88
|
issue 1
51-57
EN
Results of angular correlation of annihilation radiation and positron an­nihilation lifetime measurements are presented for five styrene copolymers: poly(co-styrene-phenylmaleimide) and its three derivatives with chlorine as well as for one with the OH group substituted in the benzene ring. It occurs that the chlorine substituted in three different positions in the benzene ring poly(co-styrene-o (or -m, -p)-chlorophenylmaleimide) inhibits the formation of the positronium to different extent. The greatest effect is observed in case of the chlorine atoms substituted in the benzene ring at ortho-position towards the nitrogen atom. In addition, electric dipole moments were measured for N-X-phenylmaleimide units, to check whether their magnitude influences the positron annihilation parameters. On the basis of the present results no correlation between the positron annihilation parameters and the electric dipole moments of the units was noticed.
10
Content available remote

Free Volume in Epoxy-Coal Resins Studied by Positron Annihilation

51%
Baranowski A., Dębowska M., Jerie K., Kurzeja L., Hennek K., Rudzińska-Girulska J.
Acta Physica Polonica A
|
1995
|
vol. 88
|
issue 1
43-49
EN
In this paper the macroscopic properties of the tetrafunctional epoxy resin (N, N'-tetraglycidyl ether of diaminodiphenylmethane) cured by 4, 4'-diaminodiphenylmethane, were studied. For the system the influence of various curing conditions on the glass temperature was investigated. Results obtained for two compositions: an unmodified one and a modified with coal were compared with information on the free volume given by the positron annihilation technique.
11
Content available remote

A New Approach for Transformer Cooling Systems: Application of Phase Change Materials (PCM)

51%
Buyukbicakci E., Temiz I., Edral H., Buyukbicakci Z.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1013-1015
EN
Cooling transformer materials are used for heat storage. In this study, phase change materials (PCM) were investigated in order to use them as alternative materials in cooling systems. PCM materials were tested and the results are presented. A transformer heating model was designed, heating spots were cooled down by application of PCM material to the model transformer. At the end of the study it was observed that heated phase change materials (PCM) kept cool during the same time period, compared to the control experiment.
12
Content available remote

Carbon Black--polyethylene Composites Studied by Positron Annihilation

51%
Dębowska M., Rudzińska-Girulska J., Pasternak A., Poźniak R.
Acta Physica Polonica A
|
1999
|
vol. 95
|
issue 4
509-514
EN
Preliminary results of positron annihilation lifetime measurements, performed for carbon black-LDPE composites with three kinds of carbon black (PRINTEX XE2, VULCAN XC-72, and SAKAP 6) are presented. Four components with lifetimes τ_{1}≈ 120 ps, τ_{2}≈340 ps, τ_{3}≈1.2 ns, τ_{4}≈2.8 ns occurred to be the best fitted to measured positron lifetime spectra. The presence of carbon black resulted only in reduction of intensities of the components with the lifetimes τ_{1}, τ_{3}, τ_{4} (originating in our opinion from the annihilation of the positronium) and increase in the intensity of the component with the lifetime τ_{2}. The intensities depend both on the content of carbon black and its kind as well. The strongest influence of the carbon black of the highest specific surface area (PRINTEX XE2) has been observed at the intensities which correlate well with the results of studies of resistivity and tensile strength for the same samples.
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