Wyniki wyszukiwania - BazTech

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Magnesium silicate conjugated with calcium lignosulfonate: In situ synthesis and comprehensive physicochemical evaluations

Klapiszewski Ł., Zietek J., Ciesielczyk F., Siwinska-Stefanska K., Jesionowski T.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

793--802

EN

The aim of this study was to effectively combine synthetic magnesium silicate with the lignin-derived biopolymer calcium lignosulfonate, using the in situ sol-gel route. Magnesium ethoxide and tetraethoxysilane were used as precursors of MgO and SiO2. The synthesis was carried out in alcoholic solution with the addition of ammonia solution as a promoter of hydrolysis. Calcium lignosulfonate was introduced to the reaction medium prior to the synthesis of magnesium silicate. The resulting hybrid powder material was thoroughly characterized, including morphology and particle sizes (SEM microscopy and the DLS technique), porous structure parameters (the BET method and BJH model), thermal stability (TG analysis) and electrokinetic stability (LDV measurements). FTIR spectral analysis was carried out to confirm the effectiveness of the proposed synthesis methodology. Based on the results, a mechanism is proposed for the MgSiO3/lignosulfonate interactions. The resulting novel type of hybrid material combines the multifunctional nature of the biopolymer (diversity of functional groups) with the well-developed porous structure of synthetic magnesium silicate. Its physicochemical parameters were found to depend significantly on the quantity of lignosulfonate used in the synthesis.

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Hydroxyapatite as a support in protease immobilization process

Zdarta J., Budzinska K., Kolodziejczak-Radzimska A., Klapiszewski Ł., Siwinska-Stefanska K., Bartczak P., Piasecki A., Maciejewski H., Jesionowski T.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 2

633--646

EN

Hydroxyapatite is used as a matrix for immobilization of protease from Aspergillus oryzae by a process of adsorption. The matrix obtained has the surface area of 26 m2/g and particles in the shape of flakes of diameters no greater than 650 nm. The efficiency of the proposed method was confirmed by the Fourier transform infrared spectroscopy, elemental analysis and by analysis of parameters of the pore structure of matrix and products after immobilization. On the basis of the Bradford method it was found that the greatest amount of enzyme (132 mg/g) was immobilized from a solution of initial enzyme concentration of 7 mg/cm3 after 24 h of the process.

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Synthesis and physicochemical characteristics of titanium dioxide doped with selected metals

Siwinska-Stefanska K., Paukszta D., Piasecki A., Jesionowski T.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 1

265--276

EN

The paper details with of the preparation and physicochemical characterisation of nano- and microstructured TiO2 doped with Fe and Co produced by the sol-gel method using titanium alkoxide as the precursor of titania as well as iron or cobalt nitrates as dopant sources. Fe and Co doped TiO2 materials were successfully prepared with two different methods. The effect of the dopant type on the synthesis of TiO2 powders was investigated. The physicochemical properties of the studied samples were determined. The characterisation included determination of the dispersion and morphology of the systems (particle size distribution, SEM images), characteristics of porous structure (BET isotherms), crystalline structure (XRD), surface composition (EDS), as well as thermal stability (TG/DTA).

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Synthesis and characterisation of SiO2/POSS hybrid systems obtained using the mechanical method

Szwarc K., Siwinska-Stefanska K., Marciniec B., Jesionowski T.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 1

181-192

EN

Hybrid systems of silica and polyhedral oligomeric silsesquioxanes (SiO2/POSS) were obtained by the mechanical method with the use of spherical or hydrated silicas, precipitated in the emulsion or aqueous environment. The SiO2 surface was modified with the following cage silsesquioxanes: hepta(isobutyl)2-triethoxysilylethyloctasilsesquioxane, octakis ({3-glycidoxy-propyl}dimethylsiloxy)octasilsesquioxane and octakis ({3-methacryloxypropyl} dimethylsiloxy)-octasilsesquioxane. The nanofillers obtained were subjected to thorough dispersive analysis (NIBS method) and morphological analysis (transmission electron microscopy). Their wettability in water systems was evaluated and their adsorption activity was characterised by determination of the specific surface area BET, pore diameters and volume. Thermal stability of the nanofillers was checked. The effect of surface modification on the degree of coverage was assessed on the basis of elemental analysis.

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Adsorption of c.i. basic blue 9 onto TiO2-SiO2 inorganic support

Przybylska A., Siwinska-Stefanska K., Ciesielczyk F., Jesionowski T.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 1

103-112

EN

Adsorption of C.I. Basic Blue 9 (Methylene Blue Hydrate) on the surface of TiO2-SiO2 oxide composite unmodified or functionalized with N-2-(aminoethyl)-3-amino propyltrimethoxsysilane was investigated. The organic dye was supported on inorganic TiO2-SiO2 oxide composite precipitated in the emulsion system. The process of adsorption was performed for the dye concentrations from 100 to 3000 mg/dm3. Specific surface area of support was determined prior to and after modification with aminosilane. The pigments obtained were subjected to characterization of their physicochemical properties, including particle size distributions and surface morphology as well as colorimetric analysis. Elemental analysis allowed evaluation of the degree of support coverage with the dye. The data obtained permitted assessment of the pigments quality and the effectiveness of support surface modification.