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1
Content available remote Katalizator żelazowy do syntezy amoniaku
100%
Lubkowski K. , Ściążko A.
Przemysł Chemiczny
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2020
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tom T. 99, nr 2
270--277
PL
Przedstawiono w sposób syntetyczny dorobek badawczy, jaki został zgromadzony w obszarze zagadnień związanych z syntezą amoniaku, w szczególności ten, który dotyczy wytwarzania i struktury katalizatora żelazowego, a także metod oraz warunków jego redukcji i pasywacji.
EN
Fundamentals and a review with 164 refs.
2
Content available The influence of sulfur addition on the hazard-type reaction of ilmenite ores with sulfuric acid
80%
Jabłoński M. , Lubkowski K. , Tylutka S. , Ściążko A.
Polish Journal of Chemical Technology
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2021
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tom Vol. 23, nr 3
17--23
EN
The paper presents results of thermokinetic investigation of the hazard-type reaction of Norwegian and Australian ilmenite ores with sulfuric acid, modified by the addition of elemental sulfur, to increase the process safety in industrial conditions. In the reactions of both ilmenite ores the addition of sulfur caused a reduction of the thermal power generated in the reaction and a decrease in the value of the thermokinetic parameter ΔTmax/Δτ for almost the whole range of initial concentrations of sulfuric acid. It was also found that the addition of sulfur to the reaction did not negatively affect the degree of ilmenite leaching. The interpretation of the obtained thermokinetic curves allowed to determine safe process conditions for both types of titanium raw materials.
3
Content available Release of selected nutrients from polymer-coated fertilisers in the soil environment
80%
Włodarczyk M. , Siwek H. , Lubkowski K. , Buchwał A.
Journal of Water and Land Development
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2024
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tom no. 62
201--211
EN
The aim of the study was to evaluate the release of NH4-N and PO4-P from polymer-coated fertilisers in the soil environment, and to analyse their impact on pH and conductivity of the soil leachates. In this investigation mineral NPK(S) 6-20-30(7) fertiliser (as a starting material), commercial, controlled-release OsmocoteTM fertiliser (as a reference material) and four polymer-coated fertilisers have been used. Biodegradable polybutylene(succinate-co-dilinoleate), polyethylene(succinate-co-terepftalate) and chitosan have been used as coating materials. The experiments were conducted in the laboratory conditions, in PVC columns filled with air-dry soil. The nutrients release from the investigated materials was explained based on the diffusion mechanism and it was interpreted with the use of the Korsmeyer-Peppas kinetic model. Two mechanisms dominate in the release process of nutrients: the mechanism based on quasi-Fickian diffusion and non-Fickian (anomalous case) mechanism. The largest changes of pH and electrical conductivity (EC) of soil leachates occurred in the initial period of research for all tested fertilisers (pH: 9.5-20.3% - loamy sand (S1) 7.9-20.6% – sandy loam (S2); EC: 438-1667% - S1, 771-1509% - S2). The polymer coating significantly reduces the nutrient release from the fertiliser core. The size of these changes depends on the type and thickness of the polymer layer and the physicochemical properties of the soils.
4
Content available Heat effects in the reaction of sulfuric acid with ilmenites influenced by initial temperature and acid concentration
80%
Jabłoński M. , Lubkowski K. , Tylutka S. , Ściążko A.
Polish Journal of Chemical Technology
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2021
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tom Vol. 23, nr 3
37--42
EN
The influence of temperature and sulfuric acid concentration on the enthalpy and the rate of heat release during the reaction of Norwegian and Australian ilmenites with sulfuric acid was determined. The experimental results obtained from calorimetric measurements were compared with theoretical calculations based on the oxide composition and the phase composition of the raw material. Experimentally determined heat of reaction for Norwegian ilmenite (900–940 kJ/kg) and Australian ilmenite (800–840 kJ/kg) showed good agreement with theoretical calculations based on the phase composition of the raw material. It was found that the enthalpy of ilmenites decomposition reaction does not depend on the concentration of sulfuric acid in the concentration range from 83% to 93%. It was also demonstrated that the temperature and concentration of sulfuric acid have a significant impact on the thermokinetics of the decomposition process, increasing the value of the average rate of temperature change.
5
Content available Ethylcellulose as a coating material in controlled-release fertilizers
61%
Lubkowski K. , Smorowska A. , Sawicka M. , Wróblewska E. , Dzienisz A. , Kowalska M. , Sadłowski M.
Polish Journal of Chemical Technology
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2019
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tom Vol. 21, nr 1
52--58
EN
Ethylcellulose polymer was used as a coating material in the preparation of controlled release fertilizers. The materials have been prepared with the use of an immersion method. The mass ratio of polymer to fertilizer was in the range of 0.165–0.285 and the layer thickness was in the range of 204–244 μm. Mechanical properties of the prepared materials were significantly better in comparison with the initial fertilizer. Measurements of time and the degree of release of mineral components from the obtained materials were determined with a standard method. Ethylcellulose-coated materials have met the requirements of controlled release fertilizers.
6
Content available Enthalpy of isopropanol adsorption on zeolite
51%
Jabłoński M. , Dzienisz A. , Sawicka M. , Wróblewska E. , Lubkowski K. , Dąbrowska G. , Piz M. , Sreńscek-Nazzal J.
Polish Journal of Chemical Technology
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2019
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tom Vol. 21, nr 4
58--65
EN
The enthalpy of isopropanol adsorption on ZSM-5 (Zeolite Socony Mobil Framework Type MFI) was determined by the static adsorption method at the temperature range from 20°C to 100°C. Langmuir and Huttig models of equilibrium adsorption have been used to calculate the enthalpy of isopropanol adsorption at these conditions. Adsorption isotherms determined by the flow method at 20°C and 30°C have been also used in the calculations. The obtained values of isopropanol adsorption enthalpy were compared with the values of isopropanol evaporation enthalpy and with the results obtained from isopropanol and water desorption measurements with thermogravimetry and differential scanning calorimetry methods.
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