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    Wyświetlanie 1-12 z 12
    Tytuł:
    Separation and physicochemical properties of residual carbon in gasification slag
    Autorzy:
    Fan, Xiaoting
    Fan, Panpan
    Liu, Xiaodong
    Ren, Zhenyang
    Bao, Weiren
    Wang, Jiancheng
    Dong, Lianping
    Fan, Minqiang
    Powiązania:
    https://bibliotekanauki.pl/articles/2175447.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    waste treatment
    gasification slag
    physical properties
    chemical properties
    structural features
    reaction kinetics
    Opis:
    Gasification slag is the solid waste produced in the coal gasification process, and its treatment and disposal problems are becoming more and more serious. In this study, the gasification slag produced in a chemical base in northern China and its residual carbon obtained by gravity separation of water medium were taken as the research objects, and their physicochemical properties were analyzed comprehensively. The residual carbon products, ash-rich products and high-ash products were obtained from the gasification slag after gravity separation. Under the optimal structure, the ignition loss of residual carbon products was reduced from 79.80% to 16.84%, and the yield was 11.64%. The high content of amorphous carbon and developed pores in the residual carbon provide the possibility of manufacturing high value-added materials. Raman spectrum showed that the residual carbon had lower aromaticity, higher content of small and medium aromatic ring structures, lower structural stability and easier combustion. Thermogravimetric combustion kinetics showed that the average combustion rate of residual carbon was 0.325(dm/dt)mean/%•min−1, the comprehensive combustion characteristic index was 1.41•10−9%2•min−2•°C−3. It has excellent performance and can be used as a raw material for mixed combustion in a circulating fluidized bed. The analysis of physical and chemical properties of residual carbon is of great significance for follow-up exploration of the resource utilization and high-value utilization of the residual carbon.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 154928
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and selected physicochemical properties of hydroxyapatite and white clay composite
    Autorzy:
    Broda, Ewa
    Skwarek, Ewa
    Payentko, Victoria V.
    Gunko, Vladimir M.
    Powiązania:
    https://bibliotekanauki.pl/articles/109703.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    hydroxyapatite
    white clay
    composite compounds
    Opis:
    Hydroxyapatite (HAP) composites are very important biomaterials, which can be applied in various life areas. HAP composite with white clay was prepared and studied using X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy (FTIR), potentiometric titration, and quasi-elastic light scattering and zeta potential measurements. The values of pHpzc (point of zero charge) and pHIEP (isoelectric point) which characterize the electrical double layer depend strongly on the white clay addition to HAP. Comparative studies of hydroxyapatite, white clay and composite using nitrogen adsorption and FTIR methods showed that in most cases composite has the properties nearly intermediate between hydroxyapatite and white clay taken for the synthesis; however, certain non- additivity was observed analyzing the properties, due to precipitation of HAP onto clay particles that changes the HAP formation conditions in comparison to HAP formation alone. Thus, changes in the condition of the composite preparation allow one to control the properties of the final materials.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1475-1483
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Physicochemical properties and NH3-SCR catalytic performance of intercalated layered aluminosilicates
    Autorzy:
    Szymaszek-Wawryca, Agnieszka
    Díaz, Urbano
    Samojeden, Bogdan
    Motak, Monika
    Powiązania:
    https://bibliotekanauki.pl/articles/24085707.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    bentonite
    DeNOx
    pillaring
    iron
    copper
    Opis:
    The representative of natural layered clays, bentonite, was modified according to two routes and tested as a new catalyst for selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR). The natural acid-activated clay was ion-exchanged with Na+ or remained in H-form and pillared with metal oxides. In order to limit the number of synthesis steps, iron as an active phase was introduced simultaneously with Al2O3 during the intercalation procedure. Additionally, the samples were doped with 0.5 wt% of copper to promote low-temperature activity. It was found that the performed modifications resulted in disorganization of the ordered layered arrangement of bentonite. Nevertheless, acid activation and pillaring improved structural and textural parameters. The results of catalytic tests indicated that the samples containing Fe2O3 pillars promoted with Cu exhibited the highest NO conversion of 85% at 250°C (H-Bent-AlFe-Cu) and 75% at 300°C (Na-Bent-AlFe-Cu). What is important, activity of the protonated samples in the high-temperature region was noticeably affected by the side reaction of ammonia oxidation, correlated with the production of NO and resulting in N2O emission during the process comparing to Na-Bentonite catalysts.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 4; art. no. 171381
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Physicochemical properties of pseudobrookite Fe2TiO5 synthesized from ilmenite ore by co-precipitation route
    Autorzy:
    Mahmoud, Mohamed H. H.
    Hessien, Mahmoud M.
    Alhadhrami, Abdulrahman
    Gobouri, Adel A.
    Powiązania:
    https://bibliotekanauki.pl/articles/109822.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    ilmenite ore
    pseudobrookite
    Co-precipitation
    nanocrystalline
    magnetic properties
    Opis:
    Pseudobrookite (Fe2TiO5) is a semiconductor with numerous potential applications. Low-grade ilmenite ore has been used as an inexpensive source of Fe and Ti for preparation of Pseudobrookite. Ilmenite was first leached with 20% hydrochloric acid for 3 h at 70°C. Co-precipitation of soluble Fe and Ti from the rich filtrate was carried out at pH ≥ 9.1 followed by calcination at different temperatures (900-1300oC) for 2 h. X-ray diffraction patterns (XRD) showed that a single-phase nanocrystalline pseudobrookite powder was produced. The pH was a critical parameter for the evolution of formation the different sizes, structural morphology, and the magnetic properties of the product. Scanning electron microscope (SEM) images showed that particles synthesized at pH 11.2 contained more agglomerations and were more porous than those synthesized at pH 9.1. As the calcination temperature increases, the Fe2TiO5 changes from a small rod-like structure to an elongated rod-like structure, and finally to interconnected aggregated crystals. The magnetization of the synthesized Fe2TiO5 was measured using a vibrating sample magnetometer (VSM) and was found steadily increase with increasing calcination temperature from 1000 (≈9 emu/g) to 1300°C (16 emu/g). Such a large saturation of magnetization might be due to the high phase purity and well-defined crystallinity of Fe2TiO5.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 1; 290-300
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and characterization of polymer biocomposites with lignin
    Autorzy:
    Goliszek, Marta
    Podkościelna, Beata
    Powiązania:
    https://bibliotekanauki.pl/articles/110212.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    lignin
    biocomposites
    physicochemical properties
    eco-filler
    photopolymerization
    Opis:
    A new method of synthesis of polymer biocomposites with lignin using the photopolymerization method has been proposed. Bisphenol A glycerolate (1 glycerol/phenol) diacrylate (BAGDA) was used as a main monomer and 2-ethylhexyl acrylate (EHA) as a reactive diluent. Lignin (L) was applied as an eco-filler. The influence of the increasing lignin content (0; 2.5; 5; 10; 20% w/w) on the properties of the obtained biocomposites was investigated. The chemical structure of biomaterials was investigated by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR) method while the thermal properties were studied by the differential scanning calorimetry (DSC) and thermogravimetric analysis (TG/DTG). Their hardness was measured by the Shore D method. Incorporation of the biopolymer into the structure of polymer composites could be a promising alternative to synthetic materials and would contribute to better lignin utilization. The results of the study are of practical importance in prospective applications of biocomposites with lignin.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1375-1381
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Some applications of barium titanate prepared by different methods
    Autorzy:
    Sydorchuk, Volodymyr
    Khalameida, Svitlana
    Skwarek, Ewa
    Biedrzycka, Adrianna
    Powiązania:
    https://bibliotekanauki.pl/articles/2146894.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    barium titanate
    synthesis
    physicochemical properties
    photocatalytic properties
    Opis:
    The paper presents some application of barium titanate synthesized by different methods. Barium titanate samples were prepared by four procedures: solid state, mechanochemical as direct synthesis and modification as well as hydrothermal and microwave. The obtained samples were systematically studied using X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy (FTIR), potentiometric titration, and quasi-elastic light scattering and zeta potential measurements. The values of pHpzc (point of zero charge) and pHIEP (isoelectric point) characteristic of the electrical double layer were determined. The prepared samples were tested as photocatalysts under visible light. As a result, relationship between the conditions of barium titanate synthesis, its physicochemical and electrokinetic parameters, as well as photocatalytic activity under visible light was first established.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2022, 58, 2 (Special issue - selected papers conference: Physicochemistry of interfaces - instrumental methods); art. no. 147192
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Activated biocarbons obtained from lignocellulosic precursors as potential adsorbents of ammonia
    Autorzy:
    Jedynak, Katarzyna
    Charmas, Barbara
    Powiązania:
    https://bibliotekanauki.pl/articles/24085696.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    activated biocarbon
    various carbon precursors
    physical activation
    physicochemical properties
    ammonia adsorption
    Opis:
    The investigated materials were new biocarbons: FC (Fir Cone), FS (Fir Sawdust), FB (Fir Bark), BS (Birch Sawdust), BB (Birch Bark), AS (Acacia Sawdust), AB (Acacia Bark), OS (Oak Sawdust), OB (Oak Bark), HS (Hornbeam Sawdust)) obtained via pyrolysis and CO2 activation of wood waste (lignocellulosic biomass). In order to study the influence of the carbon precursor on the physicochemical properties of biocarbons there were used the precursors: cones, sawdust, and bark of various tree species. The obtained adsorbents were characterized based on the results, of the N2 adsorption, scanning electron microscopy (SEM), elemental analysis (CHNS), thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), Fourier Transform Infrared Spectroscopy FT-IR (ATR) and the Boehm’s titration method as well as pHpzc (the point of zero charge). The adsorption capacity and the temperature-programmed desorption (TPD) of ammonia were also studied. The obtained activated biocarbons were characterized by the large specific surface area (515 to 1286 m2/g) and the total pore volume (0.27 to 0.46 cm3/g) as well as the well-developed microporous structure (76 - 90%). The maximum NH3 adsorption capacity of the activated biocarbon was determined to be 2.93 mmol/g (FC (Fir Cone)). These results prove that the lignocellulosic precursors are appropriate for preparation of environmentally friendly and cost-effective biocarbons.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 4; art. no. 169835
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Advanced biocomposites based on silica and lignin precursors
    Autorzy:
    Klapiszewski, Ł.
    Nowacka, M.
    Szwarc-Rzepka, K.
    Jesionowski, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/110719.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    biocomposites
    silica
    lignin
    physicochemical and structural properties
    Opis:
    A new method is proposed for obtaining biocomposites based on a combination of silica and lignin precursors. Amorphous silica was produced by two methods: one based on hydrolysis and condensation of tetraethoxysilane (sol–gel method) and the other involving precipitation in a polar medium. Additionally, the commercial silica known under the name of Syloid®244 was used. The silica surface was modified to ensure better affinity of the support to activated lignin. The biocomposites obtained were carefully characterised by determination of their physicochemical and dispersive–morphological properties. Electrokinetic stability of the biocomposites was evaluated on the basis of zeta potential dependence on pH. Thermal stability of the biocomposites and their porous structure parameters (surface area, pore diameter and pore volume) were established. The results indicate that silica/lignin biocomposites are much promising for application in many areas of science and industry.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2013, 49, 2; 497-509
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of dry grinding on physicochemical and surface properties of talc
    Autorzy:
    Arsoy, Z.
    Ersoy, B.
    Evcin, A.
    Icduygu, M. G.
    Powiązania:
    https://bibliotekanauki.pl/articles/109327.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    talc
    grinding
    contact angle
    surface free energy
    oil absorption
    whiteness
    Opis:
    In this study the effect of dry grinding on hydrophobicity, surface free energy (SFE), particle size distribution, surface area, porosity, oil absorption, and whiteness of talc was investigated. The dry grinding was performed in a vibrating ball mill at various grinding times (5-150 min) by keeping the grinding parameters constant such as the number of ball, ball size, the amount of talc, vibration frequency and amplitude. Then, the contact angle measurements were performed on disc-shaped samples produced under a hydraulic press by using a sessile drop method with different liquids (water, formamide, diiodomethane, and ethylene glycol), and surface free energies (mJ/m2) were calculated according to OCG-AB (van Oss-Chaudhury-Good Acid-Base) method by using the obtained contact angle values. In addition, the physicochemical analyses given above were carried out for each ground sample. According to the obtained results, the water contact angle and SFE of the original sample were 63.800 and 48.70 mJ/m2, respectively. The lowest and highest contact angle values for the samples were obtained as 59.300 and 70.770 at grinding times for 5 and 15 min, respectively. It was also determined that the grinding time over 30 min showed no significant effect on the contact angle and SFE values of the samples. Similarly, the grinding time vs. SFE, and the grinding time vs. contact angle curves showed a similar trend. Parallel to the increase in the surface area upon the grinding, a small increase in the oil absorption and whiteness of talc was also determined.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 1; 288-306
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of calcination parameters on physicochemical and structural properties of co-precipitated magnesium silicate
    Autorzy:
    Ciesielczyk, F.
    Bartczak, P.
    Klapiszewski, L.
    Paukszta, D.
    Piasecki, A.
    Jesionowski, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/110710.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    magnesium silicate
    precipitation
    calcination
    WAXS
    porous structure
    Opis:
    Physicochemical properties of different oxide systems depend mostly on the method of their preparation and classification, so the main aim of the study was to obtain the MgO·SiO2 hybrid in an aqueous solution and its calcination under assumed conditions. Research scope included evaluation of the effect of the basic parameters of the calcination process (time and temperature) on the structural properties of the final materials. Products obtained by the proposed method were thoroughly characterized. The chemical composition, crystalline structure, morphology and nature of the dispersion as well as parameters of the porous structure were established. The results of research in a decisive manner confirmed the possibility of designing the properties of inorganic oxide systems such as MgO·SiO2, which will definitively scheduled into potential directions for their use.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2014, 50, 1; 119-129
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Physicochemical parameters effect on biosynthesis and properties of copper nanoparticles
    Autorzy:
    Pawlowska, Agnieszka
    Kazmierczak, Michal
    Sadowski, Zygmunt
    Powiązania:
    https://bibliotekanauki.pl/articles/110884.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    gallic acid
    green tea extract
    particle size
    polyphenols
    zeta potential
    aerobic conditions
    nitrogen atmosphere
    Opis:
    Plant extract obtained from green tea was used for the synthesis of nanoparticles under anaerobic and aerobic conditions at various ratios of the copper solution to the extract used. The smallest nanoparticles were obtained at a ratio of 1:10. The nanoparticles showed the maximum negative value of the zeta potential around pH 6. An increase in the temperature of reaction caused a decrease in the negative zeta potential value. Synthesis under nitrogen atmosphere favours the formation of smaller copper nanoparticles.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1460-1466
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of alkaline promoters on the properties of the Ni/HAp catalyst in the methane dry reforming reaction
    Autorzy:
    Cichy, Marcin
    Zawadzki, Witold
    Powiązania:
    https://bibliotekanauki.pl/articles/29521159.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    hydrogen
    synthesis gas
    nickel catalyst
    dry reforming
    coking
    alkaline promoter
    Opis:
    The reforming of methane with carbon dioxide is still of great interest due to the ever-increasing demand for synthesis gas and hydrogen. This process makes it possible to use two major gases that are considered harmful to the environment. The main problem for its commercial application is the lack of a catalyst that is both active, selective towards syngas (a mixture of hydrogen and carbon monoxide) and resistant to deactivation by coke deposition. Nickel is the most commonly used metal in methane reforming reactions due to its high activity and reasonable price. But still there is a gap in the literature for research on novel catalysts and their properties modifications devoted to strategies to reduce deactivation of the catalysts caused by the coke formation. In the present work a series of hydroxyapatite supported nickel catalysts promoted by alkali metals (Li, Na, K and Cs) were tested. The surface and structural properties of the catalysts were well characterized by physicochemical methods. Activity and selectivity were measured at 600ºC for 20 hours’ time-on-stream test. Resistance to coking was measured with Magnetic Suspension Balance. The stability of the catalyst was improved by the addition of promoters, which reduced the rate of coking. In particular, the cesium-promoted Ni/HAp catalyst significantly inhibited coke deposition, while slightly reducing methane conversion and selectivity to hydrogen.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 4; art. no. 182856
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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