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1
Content available Hydrothermal Synthesis and Characterization of Sodium Bismuth Titanatefor Photocatalytic Applications
Mesrar Mohammed, Elbasset Abdelhalim, El Mrabet Imane, Zaitan Hicham, Abdi Farid, Echatoui Nor-Said, Lamcharfi Taj-dine
Journal of Ecological Engineering
|
2023
|
Vol. 24, nr 10
185--197
EN
Sodium bismuth titanate (Na0.5Bi0.5TiO3, abbreviated NBT) ceramics underwent concurrent successful synthesis on the basis of the hydrothermal method. A selected low-temperature process of thermal treatment was conducted to obtain a highly dense morphology, produced from high purity carbonates and oxides serving as initial precursors. The presence of well-crystallized NBT in the rhombohedral phase was also found at hydrothermal temperatures of 200 °C. X-ray diffraction (DRX), Raman spectroscopy, Infrared spectroscopy (IR), and Scanning electron microscopy (SEM) analysis enabled to verify the structure, phase, morphology, and composition of the used samples. NBT ceramics exhibit features specific to relaxor ferroelectrics, with a diffusion exponent γ of up to 1.5 to promote their applications in micro-electromechanical and energy harvesting systems. The photocatalytic behaviors of NBT powders have been assessed by means of the degradation of methylene blue (MB) through UV-light irradiation. The samples prepared with precursors having a Na/Bi ratio of 0.5/0.5 showed the highest methylene blue (MB) photodegradation rate of 100% under UV irradiation for 420 minutes. In addition, photocatalytic activities under different masses and pH values were discussed for the first time. In addition, the photocatalyst has excellent stability, due to the larger particle size and surface area, which opens up new possibilities for the design of multi-component photocatalysts for future applications. The photocatalytic mechanism for the degradation of organic dyes (MB) has been principally assigned to the photoreduction process caused by superoxide radical anions (•O2−) and hydroxyl radicals (•OH).
2
Content available Biomimetyczne metody otrzymywania materiałów z wykorzystaniem organicznych prekursorów
Kogut Krzysztof, Kasprzyk Krzysztof, Kłoś Renata
Szkło i Ceramika
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2022
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R. 73, nr 4
42--46
PL
W pracy przedstawiono metody biomimetyczne otrzymywania materiałów. Przedstawiono dwa przykłady otrzymania materiałów o potencjalnym zastosowaniu w implantologii z wykorzystaniem metod hydrotermalnych oraz pirolizy i infiltracji. Jako prekursory zastosowano muszle mięczaków oraz różne gatunki drzew. Wykonano badania dyfraktometryczne oraz analizy mikroskopowe. Stwierdzono, że możliwe jest uzyskanie materiałów ceramicznych o oczekiwanej strukturze metodami biomimetycznymi.
EN
This paper presents the biomimetic methods of the obtaining materials. Two examples of the obtaining materials with the use of hydrothermal and pyrolysis and infiltration methods, with possibility to implants application, was showed. As a precursor the shells of shellfish and different type of wood was used. The X-ray and microscopic analysis were carried out. It was found that is possible to obtain the ceramic material with required structure by biomimetic methods.
3
Content available remote Synthesis of single-crystalline Pb(Zr0.52Ti0.48)O3 nanocrystals by hydrothermal method
Deng Chunyu, Qin Chaoran, Li Xinyi, Li Shaoqing, Huang Zhixiong, Zhang Lianmeng, Zhou Xuedong, Guo Dongyun, Ju Yang
Materials Science Poland
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2019
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Vol. 37, No. 3
473--481
EN
PbZr0.52Ti0.48O3 nanocrystals were synthesized by a hydrothermal method. The effect of NaOH concentration, reaction temperature and time on nucleation and growth of PbZr0.52Ti0.48O3 nanocrystals was investigated. As the 0.05 mol/L PbZr0.52Ti0.48O3 precursors were heated at 200 °C for 21 h with NaOH concentration of 0.5 mol/L, the tetragonal PbZr0.52Ti0.48O3 nanocrystals were formed, and the grain size was more than 20 nm. With increasing the NaOH concentration from 0.5 to 1.5 mol/L, the grain size of PbZr0.52Ti0.48O3 nanocrystals decreased. When the precursors were heated at different temperatures (140 °C to 200 °C) for 21 h with 1.0 mol/L NaOH, single-phase PbZr0.52Ti0.48O3 nanocrystals were obtained at 160 °C to 200 °C. With increasing the reaction temperature from 160 °C to 200 °C, the grains size of PbZr0.52Ti0.48O3 nanocrystals increased from 5 nm to 9 nm. When the precursors were heated at 160 °C in different reaction times from 6 h to 21 h, the evolution from amorphous to crystalline PbZr0.52Ti0.48O3 nanocrystals in correlation with the reaction time was observed. Single crystalline PbZr0.52Ti0.48O3 nanocrystals with narrow size distribution (from 5 nm to 9 nm) were synthesized by controlling the NaOH concentration, reaction temperature and time. The obtained results can find potential application in preparing PbZr0.52Ti0.48O3 thin films on flexible substrates.
4
Content available remote Characteristics of selected methods for the synthesis of nanometric zirconium oxide – critical review
Kwaśny J., Balcerzak W.
Technical Transactions
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2017
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Vol. 2(114)
105--118
EN
High chemical stability, resistance to changes in the pH, pressure and temperature meant that zirconium oxide is widely used in many fields. It is used in water treatment and waste water treatment processes, as well as air purification. In this paper, selected methods of nano-zirconia synthesis in liquid phase were characterized. These methods include, among others, the microemulsion method. Based on literature data, the advantages and difficulties associated with the use of each method are presented, in order to answer the question of which method of nanometric zirconium oxide synthesis in the liquid phase is the most advantageous. The authors also pointed out some directions of development for the discussed methods, which relate to, among others, solvent change and the use of additives in the form of polymers.
PL
Wysoka stabilność chemiczna, odporność na zmiany pH, ciśnienia i temperatury sprawiły, że tlenek cyrkonu znajduje szerokie zastosowanie w wielu dziedzinach. Jest stosowany w procesach uzdatniania wody i oczyszczania ścieków, a także w oczyszczaniu powietrza. W niniejszej pracy scharakteryzowano wybrane metody syntezy nanotlenku cyrkonu w fazie ciekłej. Wśród grupy tych metod wyróżnia się m.in. metodę mikroemulsji. Na podstawie danych literaturowych przedstawiono zalety i trudności związane ze stosowaniem poszczególnych metod, aby móc odpowiedzieć na pytanie, która metoda syntezy nanometrycznego tlenku cyrkonu, w fazie ciekłej, jest najkorzystniejsza. Autorzy wskazali również na pewne kierunki rozwojowe omówionych metod, które wiążą się m.in. ze zmianą polarności rozpuszczalnika i stosowaniem dodatków w formie polimerów.
5
Content available remote Otrzymywanie i charakterystyka katalizatora tytanowo-silikatowego Ti-MWW : przegląd
Milchert E., Bartkowiak M.
Przemysł Chemiczny
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2017
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T. 96, nr 1
194--200
PL
Omówiono otrzymywanie katalizatora tytanowo- silikatowego Ti-MWW metodą hydrotermalną oraz sposoby jej modyfikacji. Przedstawiono możliwości zwiększenia aktywności katalizatora w procesach utleniania przez zastosowanie posyntezowej metody jego otrzymywania. Zwrócono uwagę na dużą aktywność katalizatora w procesach epoksydacji związków nienasyconych o dużych objętościowo cząsteczkach i dużą odporność katalizatora na wymywanie tytanu. Przedstawiono wyniki fizykochemicznych badań katalizatora metodami XRD, IR i UV.
EN
A review, with 60 refs., of methods for prepn. of title catalyst and their impact on activity and selectivity in the epoxidation of unsatd. compds. with various structures.
6
Content available Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method
Łuczka K., Grzmil B., Kic B., Kowalczyk K.
Polish Journal of Chemical Technology
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2016
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Vol. 18, nr 2
131--139
EN
Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios) in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.
7
Content available remote Synthesis and photocatalytic performance of spongy ZnO microstructures
Zou Y. L., Li Y., Wang Q., An D. M., Lian X. X., Lv T.
Materials Science Poland
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2015
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Vol. 33, No. 2
230--236
EN
Spongy ZnO microstructures were synthesized via a facile hydrothermal method using zinc nitrate hexahydrate and oxalic acid as raw materials. The as-obtained ZnO were characterized by powder X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and transmission electron spectroscopy (TEM), respectively. The BET surface area and average pore size of the samples were determined by nitrogen adsorption-desorption analysis. Effects of precursor and hydrothermal temperature on the morphology and photocatalytic activity of the products were investigated. SEM and TEM analysis indicated that the as-obtained spongy ZnO microstructures consisted of a large amount of ZnO particles with the average size of about 100 to 150 nm. The photocatalytic activities of the spongy ZnO microstructures were evaluated by photodegradation of methylene blue (MB) under UV light radiation. The results indicated that the ZnO synthesized at 150 °C for 10 h showed the highest photocatalytic activity and the degradation ratio of MB reached 99.5 % for 60 min of UV light irradiation with the light intensity of 10 mW cm-2.
8
Content available Luminescence of hydrothermally fabricated PbF2:Er3+ particles and their application in bifacial silicon solar cells
Yang F, Wu C., Hao X, Chen Y., Lu J., Yang Sh.
Optica Applicata
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2014
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Vol. 44, nr 3
463--473
EN
We report the synthesis of PbF2:Er3+ particles using a hydrothermal method. The structure and upconversion emission properties of the products are investigated by scanning electron microscopy, X-ray diffractometer, Raman spectrophotometer and fluorescence spectrometry. An increase in Er3+ concentration in the crystals changes the PbF2 structure from a mixed phase to a cubic phase and decreases the grain size to nanoscale levels. Enhanced upconversion efficiency is achieved after annealing resulted from the formation of the cubic phase and the increase of grain size. The optimal Er3+ concentration is found to be 4% after annealing, and applied to the back of a bifacial silicon solar cell, maximum external quantum efficiencies of 0.38% and 0.79% are respectively obtained under 0.77 W/cm2 laser excitation (1560 nm) and AM1.5 + laser co-excitation.
9
Nanosłupki ZnO o wysokiej jakości : technologia i zastosowania
Witkowski B. S., Wachnicki Ł., Gierałtowska S., Kaszewski J., Godlewski M.
Elektronika : konstrukcje, technologie, zastosowania
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2014
|
Vol. 55, nr 9
36-38
PL
Praca przedstawia nową metodę wzrostu nanosłupków ZnO z roztworu wodnego. Metoda pozwala na wzrost nanosłupków ZnO wysokiej jakości w bardzo krótkim czasie (1-3 minuty), przy czym jest tania (zarówno prekursory jak i aparatura) i nie wykorzystuje toksycznych materiałów. Wzrost odbywa się w zaledwie 50şC przy ciśnieniu atmosferycznym w roztworze wodnym ocatnu cynku. Podłoże użyte w procesie musi być pokryte nanostrukturami złota, które zarodkują wzrost (możliwe są jednak inne metody zarodkowania wzrostu, nie wymagające użycia złota). Metoda wykorzystuje wodę i octan cynku jako prekursory. Metoda charakteryzuje się dużą powtarzalnością, dzięki czemu może zostać potencjalnie wykorzystana w przemyśle do masowej produkcji matryc nanosłupków ZnO na różnych podłożach, m.in. do zastosowań w ogniwach fotowoltaicznych, fotorezystorach czy czujnikach substancji chemicznych.
EN
We present a new technology of the growth of ZnO nanorods from the water solution.The method allows for the growth of ZnO nanorods of a very high quality in a very short time (1-3 minutes). The method is inexpensive (both technology and precursors) and non-toxic. The growth is performer at 50şC under atmospheric pressure in a water solution. The substrate used in the growth process needs to be coated with gold nanodroplets, which nucleate the growth. Water and zinc acetate are used as a oxygen and zinc precursors. The method is reproducibleand can be succesfully used in the industry for mass production of ZnO nanorods matrices on different substrates, for example in photovoltaic cells, photoresistors or sensors.
10
Content available remote Charakterystyka proszków hydroksysodalitowych otrzymywanych metodą hydrotermalną z udziałem mikrofal
Czechowska K., Mozgawa W., Psiuk B., Król M.
Materiały Ceramiczne
|
2012
|
T. 64, nr 3
393-399
PL
Hydroksysodality o ogólnej formule Na6+x [AlSiO4]6 (OH)x·nH2O (gdzie 0 ≤ x ≤ 2, 0 < n ≤ 8) są pochodnymi sodalitów; zaliczane są do klatrasilów albo zeolitów. Hydroksysodality ze względu na budowę krystalograficzną są interesujące z punktu widzenia zastosowań w procesach separacyjnych jako membrany do oddzielania małych molekuł, np. amoniaku czy wody z mieszanin gazowych lub ciekłych. Celem pracy było otrzymywanie metodą hydrotermalną z udziałem mikrofal hydroksysodalitu w postaci drobnego proszku, który mógłby być potencjalnie zastosowany do otrzymywania mikroporowatych membran hydroksysodalitowych. Próby syntezy proszku hydroksysodalitu przeprowadzano z roztworów wodnych o składzie: 1 g Si : 0,26 g Al : 16,4 g Na : 128,9 g H2O, na bazie szkła wodnego sodowego, glinianu sodu, wodorotlenku sodu oraz wody redestylowanej (produkty krajowe), w reaktorze teflonowym i suszarce mikrofalowej. Stosowano moc mikrofal w zakresie 70-200 W, a czas syntezy 30, 45 i 60 minut. Wynikiem tych prób było otrzymanie serii proszków, które poddawano charakterystyce strukturalnej metodami dyfrakcji rentgenowskiej (XRD), spektroskopii w podczerwieni (IR) oraz skaningowej mikroskopii elektronowej (SEM). W pracy wykazano możliwość otrzymania drobnego proszku hydroksysodalitu o aglomeratach o wielkości ok. 2 µm (SEM) i wielkości krystalitów ok. 50 nm (XRD) przy zastosowaniu mocy mikrofal 150 W w czasie 60 min. Wyniki pracy posłużą do przeprowadzenia prób otrzymania na większą skalę proszków hydroksysodalitowych celem wytworzenia z ich udziałem mikroporowatych warstw membranowych na nośnikach ceramicznych metodą "seeding and secondary growth", przeznaczonych do zastosowań w procesach odwadniania alkoholi np. izopropanolu czy etanolu.
EN
Hydroxysodalites having the general formula of Na6+x [AlSiO4]6 (OH)x nH2O (where 0 ≤ x ≤ 2, 0 < n ≤ 8) are derivatives of sodalites, and belong to the group of clathrasils or zeolites. In terms of crystallographic structure, hydroxysodalites are interesting from the point of view of their application as a material for membranes used in processes of small molecule separation, eg. ammonia or water from gaseous or liquid mixtures. The aim of the work was to obtain fine powders of hydroxysodalite by the microwave hydrothermal method. The powders were synthesized from aqueous solutions having the composition of 1 g Si : 0,26 g Al : 16,4 g Na : 128,9 g H2O made on the basis of soda-water-glass, sodium aluminate, sodium hydroxide and redistilled water, using a Teflon reactor and a microwave dryer (as a source of microwaves). The power of microwaves within the range of 70-200 W and the times of 30, 45, and 60 minutes were applied. The obtained series of powders were characterized by the XRD, IR and SEM methods. The possibility of obtaining hydroxysodalite powder with the size of agglomerates reaching approx. 2 µm (SEM) and the size of crystallites of approx. 50 nm (XRD), using 150-W microwave power for 60 min was shown. The results of the work will be used to develop a greater-scale production of hydroxysodalite powders for microporous membrane layers on ceramic supports designed for use in processes of alcohol dehydration, e.g. propan-1-ol or ethanol, and manufactured by the seeding and secondary growth hydrothermal method.
11
Content available remote The effect of hydrothermal temperature on the synthesis of monoclinic bismuth vanadate powders
Zhang A., Zhang J.
Materials Science Poland
|
2009
|
Vol. 27, No. 4/1
1015--1023
EN
Pure phase monoclinic bismuth vanadate powders of a nanosized diameter were synthesized by the hydrothermal method and characterized using XRD, TEM, DRS, Raman and FTIR techniques. The results revealed that the hydrothermal conditions (16 h at 140-240 °C) are favourable for the formation of monoclinic bismuth vanadate powders. They also indicated that if samples are prepared by the route described in this paper, an increase in the grain size and a gradual decrease of the band gap occur as the hydrothermal temperature increases.
12
Content available remote Enhancement of ferromagnetic properties in Ni-doped BiFeO3
Wang Y., Xu G., Yang L., Ren Z., Wei X., Weng W., Du P., Shen G., Han G
Materials Science Poland
|
2009
|
Vol. 27, No. 1
219--224
EN
Ni-doped BiFeO3 samples were successfully synthesized by a hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS). It was found that the magnetization can be controlled by the Ni doping concentration. The magnetization of Ni-doped BiFeO3 was greatly enhanced when the Ni doping concentration was 0.5%. Therefore, it would be interesting to fabricate thin films with similar composition and study their properties with the aim of identifying new device applications.
13
Content available remote New magnetic Ni-Al hydrotalcite-like materials: synthesis and characterization
Wang J., You J., Yang P., Li Z., Zhang M., Jing X.
Materials Science Poland
|
2008
|
Vol. 26, No. 3
591--599
EN
Novel magnetic Ni-Al hydrotalcite with Ni/Al molar ratio of 3 was synthesized by the hydrothermal method and co-precipitation. The obtained material was characterized in detail by thermogravimetric analysis – differential scanning calorimetry, X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). XRD analysis indicated that a more well-crystallized hydrotalcite-like phase and higher thermal stability were present in the hydrothermally treated product than in that obtained by the conventional co-precipitation method. Well-defined flat particles were observed by TEM, and the (200) lattice plane (d = 0.21 nm) could be clearly seen in the HRTEM image. Furthermore, VSM results showed that the obtained material exhibited paramagnetism.
14
Preparatyka i właściwości luminescencyjne nanomateriałów dielektrycznych domieszkowanych jonami ziem rzadkich.
Hreniak D., Stręk W., Wrzyszcz J.
Archiwum Nauki o Materiałach
|
2003
|
T. 24, nr 4
611-625
PL
Przedstawione zostały metody syntezy nanorozmiarowych kryształów zawierających optycznie aktywne jony ziem rzadkich. W szczególności omówiono metody hydrotermalne, zol-żelowe i Pechini'ego oraz przedstawiono podstawowe właściwości strukturalne i spektroskopowe wybranych nanokryształów ZnAl2O4, BaTiO3, Al2O3-ZrO2 i Y3Al5O12 domieszkowanych jonami Eu 3+, Nd 3+ i Tb 3+.
EN
Techniques of preparation of nanosized crystals doped with rare earth ions have been presented. Particularly, hydrothermal, sol-gel and Pechini's methods have been described. Structural and spectroscopic properties of selected ZnAl2O4, BaTiO3, Al2O3-ZrO2 and Y3Al5O12 doped with Eu 3+, Nd 3+ and Tb 3+ ions have been investigated.
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