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  • Author: Andrzej Krysztafkiewicz x
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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

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

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.

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.