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1
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Controlled release fertilizers

100%
Lubkowski K., Grzmil B.
Polish Journal of Chemical Technology
|
2007
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vol. 9
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issue 4
83-84
EN
The efficiency of nitrogen assimilation by plants is rather low and this is a serious problem in view of environmental protection. Improvement of nitrogen absorption can be carried out through the developing, producing and applying the controlled release fertilizers. Biodegradable chitosan has been proposed as an alternative material in the production of controlled release fertilizers.
2
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The influence of admixtures on the course of hydrolysis of titanyl sulfate

81%
Grzmil B., Grela D., Kic B., Podsiadły M.
Polish Journal of Chemical Technology
|
2008
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vol. 10
|
issue 3
4-12
EN
The study focused on the question how admixtures, such as iron(II), iron(III), magnesium and aluminium salts influence the degree of TiOSO4 conversion to hydrated titanium dioxide (HTD). Titanyl sulfate solution, an intermediate product in the industrial preparation of titanium dioxide pigments by sulfate route was used. The admixtures were added to the solution and their concentration was gradually changed. It was found that hydrolysis clearly depended on Fe(II) and Fe(III) concentrations. The higher the concentration of iron(II) (up to 5 wt %) in the solution was, the higher conversion degree was achieved. A reverse relationship was observed concerning the influence of iron(III) introduced up to 1.5 wt %. The constant rates of both phases of titanyl sulfate hydrolysis (including the formation of an intermediate colloidal TiO2 and final products) depended on iron(II) and iron(III) content in the solution. The concentration of other constituents did not influence hydrolysis in the investigated part of the process (up to 2.6 wt % of Mg and up to 0.3 wt % of Al). However, the size of primary particles of the obtained TiO2·nH2O did not depend on the content of the above-mentioned constituents in the solution.
3
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A preliminary study on antifungal effect of TiO2-based paints in natural indoor light

81%
Markowska-Szczupak A., Ulfig K., Grzmil B., Morawski A.
Polish Journal of Chemical Technology
|
2010
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vol. 12
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issue 4
53-57
EN
The antifungal activity of four commercial photocatalytic paints (KEIM Ecosil ME, Titanium FA, Photo Silicate and Silicate D) in natural indoor light was investigated. The paints contained TiO2 in rutile and anatase crystalline forms as evidenced by means of the X-ray diffraction analysis. In most cases the paints inhibited growth of fungi viz. Trichoderma viride, Aspergillus niger, Coonemeria crustacea, Eurotium herbariorum, and Dactylomyces sp. The KEIM Ecosil ME paint displayed the highest antifungal effect in the light, which could be explained with the highest anatase content. The paint antifungal activity and the fungal sensitivity to the TiO2-mediated photocatalytic reaction both decreased in the following orders: KEIM Ecosil ME > Titanium FA > Photo Silicate > Silicate D and T. viride > Dactylomyces sp. > A. niger > E. herbariorum.
4
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Study of the anatase to rutile transformation kinetics of the modified TiO2

81%
Grzmil B., Gleń M., Kic B., Lubkowski K.
Polish Journal of Chemical Technology
|
2013
|
vol. 15
|
issue 2
73-80
EN
TiO2 attracts much interest because of its many potential applications. The use of titanium dioxide strongly depends on its polymorphic form: brookite, anatase, or rutile. Only rutile and anatase play an important role in industry. Anatase as a metastable form undergoes a non-reversible transformation into rutile. Understanding the kinetics of phase transformation and the processes of crystal growth of a material is essential for controlling its structure and, thus, its specific properties. The main purpose of this paper is to explain the anatase to rutile recrystallization kinetics in the modified TiO2 calcined from industrial hydrated titanium dioxide. The apparent activation energy of anatase to rutile transformation and the average size of titanium dioxide crystallites were determined for the unmodified TiO2 and TiO2 modified with P, K, Al, B, Zn, Zr, Ce, Sn, or Sb introduced in the amount of 0.5 mol% and 1.0 mol% when recalculated for their oxides. The growth of TiO2 crystallites during calcination was strongly inhibited by P, Ce and Zr, and inhibited to a lesser degree by Al, Sn and Sb. B and Zn did not affect the investigated process and K accelerated crystallites growth. The values of apparent activation energy depending on a modifier formed a relationship: Al
5
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Preparation of the TiO2photocatalyst using pressurized ammonia

81%
Wawrzyniak B., Janus M., Grzmil B., Morawski A.
Polish Journal of Chemical Technology
|
2007
|
vol. 9
|
issue 1
51-56
EN
The industrial hydrated amorphous titanium dioxide (TiO2ċ xH2O) was modified by treatment inside a chemical reactor under elevated pressure at low temperatures for 4 hours in an ammonia atmosphere. On the basis of the FTIR/DRS analysis the presence of nitrogen was confirmed. The XRD patterns of all of the catalysts exhibit mainly the diffraction lines of anatase phases. The photocatalytic activity of the modified photocatalysts was determined and compared to TiO2-P25 (Degussa, Germany). The high rate of phenol and dye degradation was obtained for the catalysts modified at 180°/15atm. TiO2-P25 showed similar activity in phenol decomposition like TiO2-15bar, whereas it was more active in dye decomposition.
6
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Influence of reduction time of copper based catalysts: Cu/Al2O3and CuCr2O4on hydrogenolysis of glycerol

81%
Wołosiak-Hnat A., Milchert E., Lewandowski G., Grzmil B.
Polish Journal of Chemical Technology
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2011
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vol. 13
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issue 4
71-76
EN
High activity of copper based catalysts for C-O bond hydro-dehydrogenation and their poor activity for C-C bond cleavage1 have prompted an attempt to apply such catalysts in the hydrogenolysis of glycerol to 1,2- and 1,3-propanediol. In the present study the influence of hydrogen reduction time of the Cu/Al2O3 and CuCr2O4 copper catalysts on glycerol conversion and selectivity of transformation to propanediols and by-products was studied. At first a general comparison was made between the commercial catalysts and those prepared by the co-precipitation method. As better results were obtained in the presence of catalysts prepared by co-precipitation, they were selected for further detailed studies of the influence of reduction time. For both prepared catalysts Cu/Al2O3 and CuCr2O4 the reduction time of 8 h was optimal. In the presence of Cu/Al2O3 catalyst the conversion of glycerol was 59.0%, selectivity of transformation to 1,2-propanediol 77.4% and selectivity to 1,3-propanediol 1.9%. In the presence of CuCr2O4 the glycerol conversion was 30.3% and selectivity to 1,2-propanediol 67.3%.
7
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The Ti-MWW catalyst - its characteristic and catalytic properties in the epoxidation of allyl alcohol by hydrogen peroxide

81%
Wróblewska A., Fajdek A., Milchert E., Grzmil B.
Polish Journal of Chemical Technology
|
2010
|
vol. 12
|
issue 1
29-34
EN
Ti-MWW, one of the latest titanium-silicalite catalysts, has been prepared by direct hydrothermal synthesis using hexamethyleneimine as a structure-directing agent. The characteristic of the catalyst was performed by means of the following methods: XRD, SEM, IR, UV-vis and X'Ray microanalysis. The catalytic properties of Ti-MWW have been compared with those of the conventional titanium-silicalites TS-1 and TS-2 in the epoxidation of allyl alcohol with hydrogen peroxide. The process has been described by the following main functions: the selectivity of the transformation to glycidol in relation to allyl alcohol consumed, the conversions of the substrates (allyl alcohol and hydrogen peroxide) and the selectivity of the transformation to organic compounds in relation to hydrogen peroxide consumed.
8
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Effects of processing parameters on hydrolysis of TiOSO4

81%
Grzmil B., Grela D., Kic B.
Polish Journal of Chemical Technology
|
2009
|
vol. 11
|
issue 3
15-21
EN
The influence of both TiOSO4 concentrations in the starting solution and a way of conducting hydrolysis on the degree of titanyl sulphate conversion to hydrated titanium dioxide were studied. Titanyl sulphate solution, an intermediate product in the commercial preparation of titanium dioxide pigments by sulphate method, was used. The continuous method of conducting hydrolysis was applied using one or two reactors connected in series. It was found that the degree of hydrolysis markedly depends on the studied parameters. It was also found that TiOSO4 hydrolysis using the continuous method should be conducted: i) at a possibly low concentration of free sulfuric acid in the solution and; ii) in two or more rectors connected in series.
9
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Studies on the transformation of calcium sulphate dihydrate to hemihydrate in the wet process phosphoric acid production

81%
Grzmil B., Kic B., Żurek O., Kubiak K.
Polish Journal of Chemical Technology
|
2012
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vol. 14
|
issue 2
80-87
EN
The influence of the process temperature from 85°C to 95°C, the content of phosphates and sulphates in the wet process phosphoric acid (about 22-36 wt% P2O5 and about 2-9 wt% SO42-) and the addition of αCaSO4·0.5H2O crystallization nuclei (from 10% to 50% in relation to CaSO4·2H2O) on the transformation of calcium sulphate dihydrate to hemihydrate has been determined. The wet process phosphoric acid and phosphogypsum from the industrial plant was utilized. They were produced by reacting sulphuric acid with phosphate rock (Tunisia) in the DH-process. The X-ray diffraction analysis was used to determine the phase composition and fractions of various forms of calcium sulphates in the samples and the degree of conversion of CaSO4·2H2O to αCaSO4·0.5H2O and CaSO4. It was found that the transformation of CaSO4·2H2O to αCaSO4·0.5H2O should be carried out in the presence of αCaSO4·0.5H2O crystallization nuclei as an additive (in the amount of 20% in relation to CaSO4·2H2O), at temperatures 90±2°C, in the wet process phosphoric acid containing the sulphates and phosphates in the range of 4±1 wt% and 27±1 wt%, respectively.
10
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The pressure method of 1-butene-3-ol epoxidation over Ti-beta catalyst

71%
Wróblewska A., Wajzberg J., Milchert E., Grzmil B., Ziebro J.
Polish Journal of Chemical Technology
|
2007
|
vol. 9
|
issue 2
53-56
EN
The investigations of 1-buten-3-ol (1B3O) epoxidation by 30% hydrogen peroxide over Ti-Beta catalyst were performed. The experiments were carried out under the autogenic pressure and at the presence of methanol as a solvent. The influence of the following technological parameters on the course of epoxidation: temperature (20 - 120°C), the molar ratio of 1B3O/H2O2 (0.5:1 - 5:1), methanol concentration (5 - 90 wt%.), Ti-Beta concentration (0.1 - 5.0 wt%) and the reaction time (0.5 - 5.0 h) was investigated. The main functions describing the process were: the selectivity of transformation to 1,2-epokxy-3-butanol in relation to 1B3O consumed, conversions of substrates as well as the selectivity of transformation to organic compounds in relation hydrogen peroxide consumed.
11
Content available remote

Photocatalytic mineralisation of humic acids using TiO2modified by tungsten dioxide/ hydrogen peroxide

71%
Tryba B., Piszcz M., Borowiak-Paleń E., Grzmil B., Morawski A.
Polish Journal of Chemical Technology
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2012
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vol. 14
|
issue 2
54-61
EN
TiO2 of anatase structure was modified by tungsten dioxide and H2O2 in order to obtain WO3-TiO2 photocatalyst with enhanced photocatalytic activity under both, UV and artificial solar light irradiations. WO2 was dissolved in 30% H2O2 and mixed with TiO2 in a vacuum evaporator at 70°C. Such modified TiO2 was dried and then calcinated at 400 and 600°C.The prepared samples and unmodified TiO2 were used for the photocatalytic decomposition of humic acids (Leonardite standard IHSS) in the aqueous solution under irradiations of both, UV and artificial solar light. Modification of TiO2 with tungsten dioxide and H2O2 improved separation of free carriers in TiO2 which resulted in the increase of OH radicals formation. Calcination caused an increase of anatase crystals and higher yield in OH radicals. The uncalcined samples showed high abilities for the adsorption of HA. Combination of adsorption abilities and photocatalytic activity of photocatalyst caused that the uncalcined TiO2 modified with WO2/H2O2 showed the shortest time of HA mineralisation. The mineralisation of HA under the artificial solar light was much lower than under the UV. It was proved that, although OH radicals are powerful in the decomposition of HA, adsorption can facilitate the contact of the adsorbed molecules with the photocatalyst surface and accelerate their photocatalytic decomposition.
12
Content available remote

Magnetic resonance study of annealed and rinsed N-doped TiO2 nanoparticles

52%
Guskos N., Typek J., Guskos A., Zolnierkiewicz G., Berczynski P., Dolat D., Grzmil B., Morawski A.
Open Chemistry
|
2013
|
vol. 11
|
issue 12
1996-2004
EN
Nanoparticles of nitrogen-modified TiO2 (N-doped TiO2) calcined at 300°C and 350°C, have been prepared with and without water rinsing. Samples were characterized by x-ray diffractrometry (XRD) and optical spectroscopy. The electron paramagnetic resonance (EPR) spectra from centers involving oxygen vacancies were recorded for all samples. These could be attributed to paramagnetic surface centers of the hole type, for example to paramagnetic oxygen radicals O−, O2−etc. The concentration of these centers increased after water rising and it further increased for samples annealed at higher temperature. Additionally, for samples calcined at 300°C, and calcined at 350°C and rinsed, the EPR spectra evidenced the presence of magnetic clusters of Ti3+ ions. The photocatalytic activity of samples was studied towards phenol decomposition under unltraviolet-visible (UV-Vis) irradiation. It was found that, in comparison to the starting materials, the rinsed materials showed increased photocatalytic activity towards phenol oxidation. The light absorption (UV-Vis/DRS) as well as surface Fourier transform infrared/diffuse reflectance spectroscopy (FTIR/DR) studies confirmed a significantly enhanced light absorption and the presence of nitrogen groups on the photocatalysts surfaces, respectively. A significant increase of concentration of paramagnetic centers connected with oxygen vacancies after water rising has had an essential influence on increasing their photocatalytic activity. [...]
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