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Teofil Jesionowski, Beata Tepper and Andrzej Krysztafkiewicz

Evaluation of colloidal silica obtained via the co-precipitation method using octane as an organic phase

The studies were conducted on the production of silica from emulsion systems by co-precipitation from solutions of sodium metasilicate and hydrochloric acid and octane were used as an organic medium. The obtained products were subjected to a comprehensive physicochemical analysis in order to define their dispersive and morphological properties. Particle diameters and polydispersity were determined by the NIBS (non-invasive back scattering) method while the shape and morphology of the particles were established using scanning electron microscopy (SEM). In order to determine the adsorptive properties of the obtained monodisperse silicas, isotherms of nitrogen adsorption/desorption on their surfaces were determined. Using the isotherms, also the specific surface area, the diameter and the volume of the pores were established. In order to define the hydrophilic/hydrophobic character of the products, profiles of wettability and of sedimentation in water were examined. The obtained products were well wettable with water and an increase in their weight depended on the amount of the applied surfactants. The particles of the precipitated silicas manifested a defined, spherical shape and showed a relatively low polydispersity.

Open access

Beata Klapiszewska, Andrzej Krysztafkiewicz and Teofil Jesionowski

Pigments precipitated from chromate post-galvanic solutions in emulsion systems

Studies were conducted on the production of chromium(III) silicates, the green pro-ecological pigments. The pigments were precipitated from sodium silicate and chromium(III) sulphate solutions in the system of two emulsions prepared in hexane in the presence of a non-ionic surfactant as an emulsifier. The chromium(III) sulphate represented a reduction product of chromate(VI) compounds present in post-galvanic wastes. The reduction agent involved metanal in an acidic medium. The obtained products were subjected to a comprehensive physicochemical analysis, their dispersive and morphological properties were determined. The precipitated green products exhibiting intense colour, were uniform and their particles manifested a low tendency to form agglomerate structures.

Open access

Anna Modrzejewska-Sikorska, Filip Ciesielczyk and Teofil Jesionowski

Synthesis of inorganic oxide composites with the use of postgalvanic waste solutions of copper(II) sulfate

The study was undertaken to obtain an oxide composite (inorganic colourful pigment) in the method based on the use of postgalvanic waste solution of copper(II) sulfate. The conditions of the process of precipitation of synthetic CuOSiO2 were optimised by checking the effect of the concentration and the volume ratio of the reagents and the temperature on the physico-chemical parameters of the final product. The oxide composite obtained in the optimum conditions was characterised by high refinement of particles and large specific surface area BET of 326 m2/g.

Open access

Łukasz Klapiszewski, Magdalena Nowacka, Katarzyna Siwińska-Stefańska and Teofil Jesionowski

Abstract

Advanced silica/lignosulfonate composites were obtained using magnesium lignosulfonate and silica precipitated in a polar medium. For comparative purposes analogous synthesis was performed using commercial silica Aerosil®200. Lignosulfonates are waste products of paper industry and their application in new multifunctional materials is of great economic interest. The composites obtained were subjected to thorough characterization by determination of their physicochemical, dispersive-morphological and electrokinetic properties. Their particle size distribution was measured, SEM images were taken, FT-IR analysis and colorimetric study were made, thermal and electrokinetic stabilities and parameters of porous structure were also determined. The results can be of interest in further application studies

Open access

Agnieszka Pilarska, Marek Lukosek, Katarzyna Siwińska-Stefańska, Krzysztof Pilarski and Teofil Jesionowski

Abstract

Synthesis of magnesium hydroxide was performed by the precipitation method with the use of magnesium sulfate and sodium hydroxide. The infiuence of temperature and ratio of reagents was studied. Magnesium hydroxides, and the magnesium oxides obtained from them by thermal decomposition, were analyzed to determine their bulk density, polydispersity and particle size. The magnesium oxide with the largest surface area was tested as a catalyst in the oxyethylation of lauryl alcohol, and shown to be selective but poorly reactive in comparison with commercially available catalysts. Further studies are needed to improve its reactivity.

Open access

Agnieszka Pilarska, Dominik Paukszta, Filip Ciesielczyk and Teofil Jesionowski

Physico-chemical and dispersive characterisation of magnesium oxides precipitated from the Mg(NO3)2 and MgSO4 solutions

An attempt was made to synthesise magnesium oxide of a high degree of dispersion permitting its use as adsorbent or catalyst. The synthesis method proposed was precipitation with the use of magnesium nitrate or magnesium sulfate. The influence of temperature, the mode and the rate of dosing, the concentration and the ratio of the reagents on the properties of the final product was analysed. Magnesium oxides were obtained by thermal decomposition of magnesium hydroxides and subjected to thorough analysis. The results permitted selection of the reaction systems ensuring synthesis of the final products of the desired properties.

Open access

Łukasz Klapiszewski, Przemysław Bartczak, Tomasz Szatkowski and Teofil Jesionowski

Abstract

We demonstrate here that lignin can be successfully combined with silica to create a multifunctional material with considerable sorption capabilities. Experiments were carried out in which a silica/lignin hybrid was used for the removal of lead(II) ions from water solutions. Adsorption kinetics were also determined and preliminary regeneration tests were performed. The effectiveness of the adsorption process depends on the following parameters: contact time of adsorbent and adsorbate (equilibrium times: 5 min for concentration 25 mg/L, 10 min for 50 and 75 mg/L, 60 min for 100 mg/L), pH (optimal pH = 5) and adsorbent mass. The kinetics of the adsorption of lead(II) ions on the SiO2/lignin biosorbent are best described by a pseudo-second-order model. Adsorption isotherms of lead(II) ions were also determined. The experimental data were found to be in agreement with the Langmuir model, and the maximal sorption capacity of the adsorbent with respect to lead(II) was 89.02 mg/g.

Open access

Teofil Jesionowski, Katarzyna Siwińska-Stefańska, Andrzej Krysztafkiewicz, Jadwiga Sójka-Ledakowicz, Joanna Koprowska and Beata Pęczkowska

Characterization of TiO2 surface following the modification with silane coupling agents

Studies were conducted on the modification of titanium white surface using selected silane coupling agents. The effect of the concentration of the organic coupling agents was examined (0.5; 1 or 3 weight parts per 100 weight parts of TYTANPOL R-003, TYTANPOL R-211 or TYTANPOL R-213 preparation of titanium white). The dispersive properties were determined by an estimation of the particle size distribution curves and of the polydispersity index. Moreover, microscopic observations were conducted permitting to evaluate the surface morphology of the modified TiO2 particles. The profiles of sedimentation in water were also determined for the titanium whites and the BET specific surface areas were determined. Selected samples of the modified and unmodified titanium whites were subjected to elemental analysis.

Open access

Teofil Jesionowski, Katarzyna Siwińska-Stefańska, Andrzej Krysztafkiewicz, Jadwiga Sójka-Ledakowicz, Joanna Koprowska and Joanna Lewartowska

The morphological and dispersive characterization of commercial titanium dioxides

The physicochemical and dispersive characterizations were conducted on the selected commercial titanium dioxides produced by, Z. Ch. POLICE, S. A. The dispersive properties were defined in detail by an analysis of particle size distribution and polydispersity index. Moreover, the microscope studies were executed to evaluate the surface morphology of the studied TiO2 forms. The profiles of titanium dioxides sedimentation in water were determined and the specific surface areas were defined by the BET method.