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  1. 16 Polish Journal of Chemical Technology
  2. 10 Physicochemical Problems of Mineral Processing
  3. 7 Polish Journal of Chemistry
  4. 2 Ecological Chemistry and Engineering. S
  5. 2 Open Physics
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  1. 2 2015
  2. 1 2013
  3. 7 2012
  4. 4 2011
  5. 11 2010
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  1. 7 Morawski A.
  2. 6 Janus M.
  3. 5 Zaleska A.
  4. 4 Grzechulska-Damszel J.
  5. 3 Bodzek M.
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1
Content available remote Photocatalytic hydrogen generation over alkali niobates in the presence of organic compounds
100%
Zielińska B. , Sreńscek-Nazzal J. , Kaleńczuk R.
Polish Journal of Chemical Technology
|
2008
|
tom 10
|
nr 4
1-3
EN
The photocatalytic efficiency of alkali niobate-based compounds (Li, Na, K) for hydrogen generation has been investigated. The systematic study showed that the highest photocatalytic activity was observed in the case of Na/Nb2O5 catalyst which contained sodium niobate (NaNbO3) phase and that the most efficient electron donor for hydrogen generation was formic acid. In addition, the effect of organic donor (HCOOH) concentration on the amount of the evolved hydrogen was studied.
2
Content available remote A preliminary study on antifungal effect of TiO2-based paints in natural indoor light
100%
Markowska-Szczupak A. , Ulfig K. , Grzmil B. , Morawski A.
Polish Journal of Chemical Technology
|
2010
|
tom 12
|
nr 4
53-57
EN
The antifungal activity of four commercial photocatalytic paints (KEIM Ecosil ME, Titanium FA, Photo Silicate and Silicate D) in natural indoor light was investigated. The paints contained TiO2 in rutile and anatase crystalline forms as evidenced by means of the X-ray diffraction analysis. In most cases the paints inhibited growth of fungi viz. Trichoderma viride, Aspergillus niger, Coonemeria crustacea, Eurotium herbariorum, and Dactylomyces sp. The KEIM Ecosil ME paint displayed the highest antifungal effect in the light, which could be explained with the highest anatase content. The paint antifungal activity and the fungal sensitivity to the TiO2-mediated photocatalytic reaction both decreased in the following orders: KEIM Ecosil ME > Titanium FA > Photo Silicate > Silicate D and T. viride > Dactylomyces sp. > A. niger > E. herbariorum.
3
Synthesis, Characterization and Photocatalytic Activity of Some TiO2/Carbon Composites
100%
Kulesius Z. , Valatka E.
|
2006
|
tom Vol. 80, nr 2
335-344
EN
Anatase-type TiO2 composites with various allotropic forms of carbon (carbon nanotubes, carbon nanofibers and activated carbon) were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, thermogravimetry-differential scanning calorimetry (TG-DSC), Fourier-transform infrared (FT-IR) and scanning electron microscopy (SEM) analysis. The synthesis of TiO2/carbon composites was carried out by using acid-catalyzed sol-gel method, followed by drying in supercritical 2-propanol. The weight ratio mTiO2/mcarbon was 4 in all prepared samples. In order to compare the photoactivity of different catalysts, the phenol degradation was employed as a test reaction
4
Content available remote Preparation of the TiO2photocatalyst using pressurized ammonia
100%
Wawrzyniak B. , Janus M. , Grzmil B. , Morawski A.
Polish Journal of Chemical Technology
|
2007
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tom 9
|
nr 1
51-56
EN
The industrial hydrated amorphous titanium dioxide (TiO2ċ xH2O) was modified by treatment inside a chemical reactor under elevated pressure at low temperatures for 4 hours in an ammonia atmosphere. On the basis of the FTIR/DRS analysis the presence of nitrogen was confirmed. The XRD patterns of all of the catalysts exhibit mainly the diffraction lines of anatase phases. The photocatalytic activity of the modified photocatalysts was determined and compared to TiO2-P25 (Degussa, Germany). The high rate of phenol and dye degradation was obtained for the catalysts modified at 180°/15atm. TiO2-P25 showed similar activity in phenol decomposition like TiO2-15bar, whereas it was more active in dye decomposition.
5
Content available remote Application of titania coating as photoactive refill in the reactor for purification of water contaminated with organics
100%
Grzechulska-Damszel J.
|
2010
|
tom Vol. 45
39-47
EN
The aim of the present work was to remove organic impurities from water using a reactor with photoactive refill. Application of the photoactive refill solves the problem of the replacement of the reactor or its parts when the photocatalyst activity decreases. In case of photocatalytic activity drop, only the photoactive refill can easily be replaced. Titanium dioxide coating was immobilized on the glass fabric as a thin layer from the alcoholic suspension followed by thermal stabilization. The results of studies revealed that the titania coating shows a high photocatalytic potential for the decomposition of the model organic compounds (azodye Acid Red 18, phenol and methylene blue) in water. The coating exhibits high stability in repeated cycles of water treatment.
6
Content available remote Strong photo-catalytic fiber and its wide application
100%
Ishikawa T.
|
2010
|
tom Vol. 45
57-71
EN
In order to avoid large problems regarding peeling of the titania layer coated on the substrate, we developed an epoch-making "strong titania fiber" consisting of photoactive surface layer with a nanometer-scale compositional gradient, which can effectively oxidize any kind of organic materials. An effective water-purification system using this fiber has been also developed. The basis of this technology is to incorporate a selected low-molecular-mass additive (Ti(OC4H9)4) into a precursor polymer from which the ceramic forms. After melt-spinning the resulting precursor polymer, thermal treatment of the spun fiber leads to controlled phase separation ("bleed-out") of the additive; subsequent calcination stabilizes the compositionally changed surface region, generating a functional surface layer. This fiber consists of the silica-based core-structure and the gradient-like surface titania layer, which are strongly sintered. We also developed a water-purifier using this fiber (felt material). Any bacteria (common bacterium, legionera pneumophila, colon bacillus, heterotrophic bacteria, and so forth) and organic chemicals (dioxin, PCB, and so forth) were effectively decomposed into CO2 and H2O passing through the above purifier.
7
Content available remote Preliminary results of glucose oxidation by photocatalysis on titanium dioxide - primary intermediates
100%
Zmudziński W.
|
2010
|
tom Vol. 45
141-151
8
Content available remote Photocatalytic activity of TiO2 loaded with metal clusters
100%
Grabowska E. , Remita H. , Zaleska A.
|
2010
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tom Vol. 45
29-38
EN
TiO2 was surface modified with silver, gold and platinum ion clusters to improve its photocatalytic activity. The effect of metal content, the kind of dopant and titanium dioxide source (commercial - P25 and ST-01) used during preparation procedure on photoactivity were investigated. The photocatalytic activity was estimated by measuring the decomposition rate of 0.21 mM phenol aqueous solution under UV-Vis and visible (λ > 400 nm). The highest photoactivity was observed for TiO2 loaded with silver (2%Ag on P25), gold (1%Au on P25) and platinum (0.5% Pt on ST-01) clusters. After 60 min. of irradiation under UV light phenol solution was degraded in 91%, 49% and 91%, respectively
9
Photocatalytic Wastewater Treatment Using the Zeolite-Y Entrapped Ruthenium Tris-2,2'-bipyridine Complex
100%
Szulbiński W.
|
2001
|
tom Vol. 75, nr 10
1543-1551
EN
The zeolite-Y entrapped ruthenium tris-2,2_-bipyridine complex, in 1% wt. metallized with platinum (Z-[Ru(bpy)3]2+/Pt), has been examined as a new photocatalyst for wastewater treatment in flow reactors of the pilot plant at the Plataforma Solar de Almeria, in Spain. The catalyst generated by the template synthesis of [Ru(bpy)3]2+ within the zeolite-Y supercages (with the occupancy of one the [Ru(bpy)3]2+ molecule per five the zeolite supercages), and then platinized of the resulting Ru intrazeolitic complex. The catalytic activity of Z-[Ru(bpy)3]2+/Pt for wastewater treatment has been compared to that of TiO2, as the standard. For this, phenol (PhOH) and pirimicarb (a pesticide) have been used as models for water pollutants. By kinetic measurements it has been documented that Z-[Ru(bpy)3]2+/Pt decomposes PhOH with the relative photonic efficiency of r = 0.37, assuming that r = 1.0 for TiO2, under the same experimental conditions. To improve the Z-[Ru(bpy)3]2+/Pt photocatalytic activity, all the zeolite supercages have to be occupied by [Ru(bpy)3]2+ molecules, since this might increase the rate of the photoinduced electron transfer reaction. Moreover, it has been revealed that Z-[Ru(bpy)3]2+/ Pt is mostly active at the visible range of the solar radiation, at which TiO2 is inactive and unable to decompose organic pollutants. This has been supported by the diffuse reflectance spectroscopic measurement exhibiting the electronic absorption of Z-[Ru(bpy)3]2+/Pt at max = 454 nm.
10
Influence of adsorption and physicochemical properties of aerogels on photocatalytic processes.
100%
Malinowska B. , Walendziewski J. , Robert D. , Weber J. V. , Stolarski M.
|
|
tom Vol. 10, nr 57
81-86
EN
Titania aerogels were prepared. Their physicochemical properties and adsorption capability were determined. Commercial TiO2 Degussa was examined for comparison. The activities of the catalysts in the photocatalytic processes were tested. Two para derivatives of phenol were chosen as model compounds (p-chlorophenol and 4-hydroxybenzoic acid). There was no dependence of surface area and acidity on photoactivity of catalysts. It depends on pollutant type and adsorption ability of photocatalysts.
11
Content available remote NOx photocatalytic degradation on gypsum plates modified by TiO2-N,C photocatalysts
100%
Janus M. , Bubacz K. , Zatorska J. , Kusiak-Nejman E. , Czyżewski A. , Morawski A. W.
Polish Journal of Chemical Technology
|
2015
|
tom 17
|
nr 3
8-12
EN
In presented studies the photocatalytic decomposition of NOx on gypsum plates modified by TiO2-N,Cphotocatalysts were presented. The gypsum plates were obtained by addition of 10 or 20 wt.% of different types of titanium dioxide, such as: pure TiO2 and carbon and nitrogen co-modified TiO2 (TiO2-N,C) to gypsum. TiO2-N,C photocatalysts were obtained by heating up the starting TiO2 (Grupa Azoty Zakłady Chemiczne Police S.A) in the atmosphere of ammonia and carbon at the temperature: 100, 300 i 600ºC. Photocatalyst were characterized by FTIR/DRS, UVVis/DR, BET and XRD methods. Moreover the compressive strength tests of modified gypsum were also done. Photocatalytic activity of gypsum plates was done during NOx decomposition. The highest photocatalytic activity has gypsum with 20 wt.% addition of TiO2-N,C obtained at 300ºC.
12
Content available remote Photoreduction of carbon dioxide with hydrogen using temperature programmed method
100%
Kocemba I. , Nadajczyk J. , Góralski J. , Szynkowska M.
Polish Journal of Chemical Technology
|
2010
|
tom 12
|
nr 3
1-2
EN
The photocatalytic reduction of carbon dioxide with hydrogen was studied by Temperature-Programmed Surface Reaction (TPSR). This process was carried out in a flow reactor that was especially designed and constructed for this purpose. Titanium dioxide (TiO2, Degussa P-25) was used as supports for platinum, ruthenium and nickel catalysts. The experimental results indicated that the activity of photoreduction of CO2 changes as follows: Ru/TiO2 > Ni/TiO2 > = Pt/TiO2 > TiO2.
13
Content available remote Carbon modified TiO2photocatalysts for water purification
100%
Morawski A. , Janus M. , Tryba B. , Toyoda M. , Tsumura T. , Inagaki M.
Polish Journal of Chemical Technology
|
2009
|
tom 11
|
nr 2
46-50
EN
Carbon can form different structures with TiO2: carbon-doped TiO2, carbon coated TiO2 and composites of TiO2 and carbon. The presence of carbon layer on the surface of TiO2 as well as the presence of porous carbon in the composites with TiO2 can increase the concentration of organic pollutants on the surface of TiO2, facilitating the contact of the reactive species with the organic molecules. Carbon-doped TiO2 can extend the absorption of the light to the visible region by the narrowing of the band gap and makes the photocatalysts active under visible light irradiation. TiO2 loaded carbon can also work as a photocatalyst, on which the molecules are adsorbed in the pores of carbon and then they undergo the photocatalytic decomposition with UV irradiation. Enhanced photocatalytic activity for the destruction of some organic compounds in water was noticed on the carbon coated TiO2 and TiO2 loaded activated carbon, mostly because of the adsorptive role of carbon. However, in carbon-doped TiO2, the role of carbon is somewhat different, the replacement of carbon atom with Ti or oxygen and formation of oxygen vacancies are responsible for extending its photocatalytic activity towards the visible range.
14
Content available remote TiO2modified by ammonia as a long lifetime photocatalyst for dyes decomposition
100%
Choina J. , Dolat D. , Kusiak E. , Janus M. , Morawski A.
Polish Journal of Chemical Technology
|
2009
|
tom 11
|
nr 4
1-6
EN
Ammonia-modified TiO2 (TiO2/N), prepared in a pressure reactor was used as the well- active and longlife photocatalyst for the azo dye (Reactive Red 198) decomposition. The effect of aeration and the different value of the pH of the reaction medium on the photocatalytic degradation of Reactive Red 198 in water has been investigated. It has been reported that the degradation is greatly influenced by the reaction pH and the faster decomposition of azo dye took place at pH 3.5. When the solution was acidic, a larger amount of azo dye on the positively charged surface of TiO2 photocatalysts was adsorbed. From the obtained results it can be seen that the effectiveness of the decolourisation of the solution was faster by using the nitrogen-modified TiO2.
15
Content available remote Comparison of NaNbO3and NaTaO3as the photocatalysts in the reaction of hydrogen generation
100%
Zielińska B. , Kaleńczuk R.
Polish Journal of Chemical Technology
|
2010
|
tom 12
|
nr 3
33-35
EN
The photocatalytic production of hydrogen over several chemical compounds based on sodium niobates and tantalates has been investigated. The photocatalysts have been prepared by an impregnation method of Nb2O5 and Ta2O5 in the aqueous solution of sodium hydroxide and then the calcination at the temperature range of 450 - 800°C. In this report, we present the study showing that of the catalysts explored, the highest photocatalytic activity was shown in a sample obtained at the temperature of 450°C and containing NaTaO3 as a main phase.
16
Content available remote Preparation and photocatalytic activity of iron- modified titanium dioxide photocatalyst
100%
Lezner M. , Grabowska E. , Zaleska A.
|
2012
|
tom Vol. 48, iss. 1
193-200
EN
Iron modified TiO2 was prepared by the sol-gel method and surface modification method followed by calcination at 400°C. Two types of titanium dioxide: TiO2 ST-01(Ishihara Sangyo Ltd., Japan;300 m2/g), and TiO2 P25 (Evonik, Germany, 50 m2/g) were used in the grinding procedure. The photocatalysts were characterized by UV-VIS absorption and BET surface area measurements. The photocatalytic activity of the obtained powders in UV-Vis and visible light was estimated by measuring the decomposition rate of phenol (0.21 mmol/dm3) in an aqueous solution. The best photoactivity under visible light was observed for iron doped TiO2 with 0.5% by grinding the TiO2 ST-01.
17
Content available remote Characterization And Photocatalytic Activity Of Rare Earth Metal-Doped Titanium Dioxide
100%
Reszczynska J. , Iwulska A. , Sliwinski G. , Zaleska A.
|
2012
|
tom Vol. 48, iss. 1
201-208
EN
The aim of this research was to prepare rare metal (Er, Yb)-modified TiO2 nanoparticles by a sol-gel method. The obtained nanoparticles were characterized by BET measurements, UV-Vis spectra and the Laser-induced fluorescence (LIF) method. Visible light photocatalytic activity of the sample was studied by photodegradation of phenol while considering the influence of the dopant concentration. The obtained results showed that a smaller amount of the dopant gave better photocatalytic activity of a semiconductor. The absorption spectra of Yb3+-doped and Er3+-TiO2 samples show stronger absorption in the UV-Vis region than pure TiO2. The presence of erbium was found more beneficial for visible light activation of TiO2 doped photocatalysts than ytterbium.
18
Influence of the adsorption on the photocatalytic reactions.
100%
Robert D. , Weber J. V.
|
|
tom Vol. 9, nr 56
129-134
EN
The photodegradation processes using semi-conductor like TiO2 as a catalyst, provide new methods for waste water treatment. In this method the step of adsorption of organic compounds on the semi-conductor surface could have a prominent influence. We describe the adsorption phenomen for two classes of organic molecules (phenolic compounds and dicarboxylic acids) studied by diffuse reflectance infrared spectroscopy (IRFT-DRIFT mode). The relations between adsorption and degradation mechanisms has been approached. In particular, we presente the results of the dicarboxylic acids and phenolic compounds adsorption on TiO2 (P25) in aqueous phase. The Langmuir model gives a good representation of the adsorption of the boths studies organic compound families. In the case of the diacid, the DRIFT spectroscopy of loaded TiO2 enables to demonstrate the formation of a dicarboxylate film on the TiO2. The adsorption of phenol molecules with the plane of the aromatic ring parallel to the TiO2 surface is observed and confirmed by skeletal pattern simplification and the disappearance of the bending O-H absorption vibration shown phenolate ions formation and bonding with TiO2.
19
Content available remote Photoluminescence and photocatalytic activity of zinc tungstate powders
100%
Gigorjeva L. , Millers D. , Grabis J. , Jankoviča D.
Open Physics
|
2011
|
tom 9
|
nr 2
510-514
EN
ZnWO4 powders with grain size in range 20 nm–10 µm have been synthesized by a simple combustion method and subsequent calcinations. The photocatalytic activities of powders were tested by degradation of methylene blue solution under UV light. The luminescence spectra and luminescence decay kinetics were studied and luminescence decay time dependence on average powder-grain size was obtained. The correlation between self-trapped exciton luminescence decay time and photocatalytic activity of ZnWO4 powders was shown. A model explaining the excitonic luminescence decay time correlation with photocatalytic activity was proposed.
20
Enhanced Activity of Nano-TiO2 in Photoelectrocatalysis over Photocatalysis Process for the Degradation of Indanthrene BR Violet Dye in Presence of UV-Light
100%
Gomathi Devi L. , Kottam N.
|
2007
|
tom Vol. 81, nr 10
1819-1819
EN
This paper reports results of an investigation of the removal of Indanthrene BR Violet (IBRV) dye in a photoelectrochemical oxidation reactor with semiconductor suspended in the aqueous solution. TiO2 nano powder is prepared by sol-gel method to improve catalytic efficiency. X-ray diffraction analysis indicated anatase crystalline form with particle size of 17.9 nm. Diffuse reflectance spectra showed that the band gap is 3.0 eV. The model compound chosen for the degradation study is Indanthrene BR Violet dye. The presence of a catalyst in the electric field can enhance the treatment efficiency. The reaction was studied at different applied potentials +2.0 V, +1.0 V, +0.1 V, +0.05 V, + 0.01 V. The study has shown that an optimum voltage is necessary for a particular degradation reaction. Finally these results are compared with the photocatalytic degradation.
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