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1
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Magnetic properties of co-modified Fe,N-TiO2nanocomposites

100%
Zolnierkiewicz G., Glenis S., Guskos N., Guskos A., Typek J., Berczynski P., Dolat D., Mozia S., Morawski A. W.
Open Physics
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2015
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vol. 13
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issue 1
EN
Iron and nitrogen co-modified titanium dioxide nanocomposites, nFe,N-TiO2 (where n = 1, 5 and 10 wt% of Fe), were investigated by detailed dc susceptibility and magnetization measurements. Different kinds of magnetic interactions were evidenced depending essentially on iron loading of TiO2. The coexistence of superparamagnetic, paramagnetic and ferromagnetic phases was identified at high temperatures. Strong antiferromagnetic interactions were observed below 50 K, where some part of the nanocomposite entered into a long range antiferromagnetic ordering. Antiferromagnetic interactions were attributed to the magnetic agglomerates of iron-based and trivalent iron ions in FeTiO3 phase,whereas ferromagnetic interactions stemmed from the F-center mediated bound magnetic polarons.
2
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Dye decomposition on P25 with enhanced adsorptivity

80%
Janus M., Wawrzyniak B., Tryba B., Morawski A.
Polish Journal of Chemical Technology
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2008
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vol. 10
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issue 2
11-16
EN
The preparation method and the activity of the TiO2-P25/N doped photocatalyst based on commercial titanium dioxide (TiO2 Aeroxide® P-25 Degussa, Germany) are presented. For the TiO2-P25/N preparation TiO2-P25 and gaseous ammonia were kept in a pressure reactor (10 bars) for 4 hours at the temperature of 200°C. This modification process changed the chemical structure of the TiO2 surface. The formation of NH4+ groups was confirmed by the FTIR measurements. Two bands in the range of ca. 1430 - 1440 cm-1 attributed to bending vibrations of NH4+ could be observed on the FTIR spectra of the catalysts modified with ammonia and the band attributed to the hydroxyl groups at 3300 - 3500 cm-1, which were not reduced after N-doping. The photocatalytic activity of the photocatalysts was checked through the decomposition of two dyes under visible light irradiation. The modified TiO2 thus prepared samples were more active than TiO2-P25 for the decomposition of dyes under visible light irradiation.
3
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A preliminary study on antifungal effect of TiO2-based paints in natural indoor light

80%
Markowska-Szczupak A., Ulfig K., Grzmil B., Morawski A.
Polish Journal of Chemical Technology
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2010
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vol. 12
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issue 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.
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Titanium dioxide high aspect ratio nanoparticle hydrothermal synthesis optimization

80%
Półrolniczak P., Walkowiak M.
Open Chemistry
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2015
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vol. 13
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issue 1
EN
TiO2-B (bronze) nanowires were synthesized via simple hydrothermal treatment of commercial titanium dioxide nanopowder in aqueous NaOH. The reaction temperature, calcination temperature, reaction time, NaOH concentration, autoclave filing fraction and precursor were systematically varied to optimize the nanowire morphology. The crystal structure, morphology and particle size were investigated by XRD, SEM and TEM. The morphology and structure are sensitive to experimental conditions. A reaction temperature of at least 150°C and NaOH concentration at least 10 M are essential, but reaction time from 24 to 72 h makes little difference. Nanowires obtained at 150°C were 60-180 nm wide and 2-4 μm long, while those after treatment at 200°C were thinner (40-100 nm) and longer (2-6 μm). The relationship between reaction conditions and morphology is discussed and practical guidelines for titanium dioxide nanowire synthesis are suggested
5
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Sensitizing of Sm3+ fluorescence by silver dopant in the TiO2 films

80%
Dolgov L., Kiisk V., Reedo V., Pikker S., Sildos I., Kikas J.
Open Physics
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2011
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vol. 9
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issue 2
542-546
EN
Composite material based on a TiO2 matrix doped with Sm3+ ions and co-doped with silver was investigated. Samarium ions together with nano- and micro-aggregates of silver were incorporated into the titanium alkoxide during the sol-gel process. Samarium ions were excited either directly (λ exc = 488 nm) or through the TiO2 host (λ exc = 355 nm). It was revealed that samarium fluorescence (λ exc = 488 nm) in gelled TiO2 films is enhanced by up to 20 times in the vicinity of silver inclusions. Sensitizing and plasmonic mechanisms of enhancement in Sm3+ fluorescence are discussed.
6
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Magnetic resonance study of co-modified (Co,N)-TiO2nanocomposites

80%
Guskos N., Zolnierkiewicz G., Guskos A., Typek J., Berczynski P., Dolat D., Mozia S., Aidinis C., Morawski A. W.
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issue 3
411-416
EN
Three nCo,N-TiO2 nanocomposites (where cobalt concentration index n = 1, 5 and 10 wt %) were prepared and investigated by magnetic resonance spectroscopy at room temperature. Ferromagnetic resonance (FMR) lines of magnetic cobalt agglomerated nanoparticle were dominant in all registered spectra. The relaxation processes and magnetic anisotropy of the investigated spin system essentially depended on the concentration of cobalt ions. It is suggested that the samples contained two magnetic types of sublattices forming a strongly correlated spin system. It is suggested that the existence of strongly correlated magnetic system has an essential influence of the photocatalytic properties of the studied nanocomposites.
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Experimental Analysis of Titanium Dioxide Synthesis from Synthetic Rutile Waste using a Moderate Acid Concentration and Temperature

80%
Ahmad Mukifza H., Awang H., Yusof S., Farid E.
Acta Physica Polonica A
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2017
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vol. 132
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issue 3
833-835
EN
The present study is to clarify the present influences of acid concentration and temperature of caustic hydrothermal method on extracting the titanium dioxide (TiO₂) from synthetic rutile waste. In this experimental work, the caustic hydrothermal method comprises two processes: a decomposition and the sulphate process. The extracted titanium is characterized by using a electron dispersive X-ray spectroscopy to specify its chemical composition, field emission scanning electron microscope to determine the morphology and particle size, and lastly it is the X-ray diffraction to analyse the crystallinity of extracted titanium. In this study, we found that both acid concentration and temperature affected the TiO₂ growth while the calcination process could improve the crystallinity of extracted titanium.
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Water purification using a novel reactor with the photoactive refill

70%
Grzechulska-Damszel J., Morawski A.
Polish Journal of Chemical Technology
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2009
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vol. 11
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issue 1
61-63
EN
The aim of the presented work was the removal of organic dye, Acid Red 18, from water using a novel reactor with the photoactive refill. Titanium dioxide was immobilized on the base material as a thin layer from the alcoholic suspension followed by thermal stabilization. The prepared coating exhibits high stability in repeated cycles of water treatment. The complete removal of colour was achieved in a relatively short time of 14 hours. The proposed reactor with the photoactive refill solves the problem of the necessity of the replacement of the reactor or parts of the reactor when the photocatalysts activity decreases. In the case of activity drop of the photocatalyst, only the photoactivve refill can be easily replaced.
9
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Removal of organic dye in the hybrid photocatalysis/membrane processes system

70%
Grzechulska-Damszel J., Morawski A.
Polish Journal of Chemical Technology
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2007
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vol. 9
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issue 2
94-98
EN
The removal of azo dye Acid Red 18 in hybrid photocatalysis/membrane processes systems was investigated. The photocatalytic reactions were conducted in the reactor with photocatalyst suspended in the solution. The reaction solution was recirculated through the ultrafiltration system. A commercially available titanium dioxide (Aeroxide® P25, Degussa, Germany) was used as a photocatalyst. The solution after the photocatalytic/UF reaction was applied as the feed for the membrane distillation process. The changes of various parameters, including the concentration of the dye, pH and the conductivity of the solution, TOC and TDS content were analyzed during the process.It was found that azo dye Acid Red 18 could be successfully decolourised in the hybrid photocatalysis/UF system. The catalyst particles were retained in the feed solution by means of the ultrafiltration membrane so the obtained permeate was free of TiO2. The application of ultrafiltration together with the photocatalytic process results in the separation of photocatalyst from the treated solution but does not give the complete removal of organic matter from the reaction mixture. Membrane distillation applied with the permeate after the photocatalysis/UF process as a feed gives a complete separation of TOC from the treated solution and the obtained product is practically pure water.
10
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Influence of Polarization Processes on the Morphology and Photoluminescence Properties of PP/TiO₂ Polymer Nanocomposites

70%
Ramazanov M., Hajiyeva F., Maharramov A., Hasanova U., Ahmadova A., Rahimli A., Shirinova H.
Acta Physica Polonica A
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2017
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vol. 131
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issue 6
1540-1543
EN
The paper reports of synthesis and investigation of polymeric nanocomposites based on isotactic polypropylene and titanium dioxide nanoparticles PP+TiO₂ (PPT). The structure of the PPT nanocomposites was studied by scanning electron and atomic force microscopy. There was also studied the influence of the polarization process by corona discharge on the structure and photoluminescence properties of PPT nanocomposites. It was found that intensity of the photoluminescence after the polarization increases, and this depends on the concentration of titan dioxide nanoparticles in the polymer matrix. It was shown that rms roughness for non-polarized sample compositions is 60-100 nm, whereas for polarized samples after the corona discharge polarization, makes 20-40 nm, i.e. there takes place grinding of the structural elements. It is supposed that, in the composite there forms sufficiently high internal local field, due to the boundary charges, so under the influence of this field there were excited additional luminescent centers, and as a result, after the polarization there was observed the increase of luminescence intensity.
11
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BEHAVIOUR OF TiO2/CHITOSAN DISPERSION AS A FUNCTION OF SOLUTION pH

70%
Gozdecka A., Wiącek A. E.
Progress on Chemistry and Application of Chitin and its Derivatives
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2017
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vol. 22
27-41
EN
This paper presents the physico-chemical characteristics of titanium dioxide/chitosan dispersion. The surface and electrostatic properties of TiO2 particles in the electrolyte solution (NaCl) and in the presence of a biopolymer were determined by static and dynamic light scattering. The stability measurements were made under different conditions, where the variable was the dispersion pH. This paper mainly includes discussion of dispersion behaviour in neutral and alkaline environments. At each pH value (6–9), the addition of chitosan caused significant improvement in stability compared to the systems of base titanium dioxide. Of the tested systems, the most stable values of diameter and zeta potential for dispersion were found at pH 7. The study allowed the conclusion that the addition of chitosan to TiO2 dispersion created the possibility of using such systems as a drug carrier for the controlled release of active substances sensitive to pH changes.
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Preliminary studies of photocatalytic activity of gypsum plasters containing TiO2co-modified with nitrogen and carbon

70%
Janus M., Bubacz K., Zatorska J., Kusiak-Nejman E., Czyżewski A., Morawski A. W.
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EN
The conducted studies were focused on the development of the gypsum material exhibiting self-cleaning properties. To this end, the raw gypsum was mixed with unique TiO2-based photocatalysts, previously modified by nitrogen and/ or carbon doping. The photocatalytic activity of the obtained gypsum plasters was evaluated trough the degradation of model organic compound (Reactive Red 198) under UV-vis irradiation. The impact of the photocatalysts presence on the physicochemical properties of the obtained gypsum plasters was evaluated. Furthermore, the role of non-metals presence on the photocatalytic properties of the TiO2 was determined. It was confirmed that the addition of N,C co-modified titanium dioxide into gypsum bestows this material with self-cleaning properties. The highest dye removal rate was displayed by the gypsum plaster containing optimal amount (10 wt%) of co-modified TiO2/N,C photocatalyst, after 20 hours of UV-vis irradiation.
13
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SURFACE CHARACTERISTICS OF DPPC MONOLAYERS DEPOSITED FROM TITANIUM DIOXIDE–CHITOSAN–HYALURONIC ACID SUBPHASES ON A GLASS SUPPORT

61%
Ładniak A., Jurak M., Wiącek A. E.
Progress on Chemistry and Application of Chitin and its Derivatives
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2019
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vol. 24
106 - 118
EN
The Langmuir-Blodgett technique was used to transfer the monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) from the subphase containing chitosan (Ch) and/or titanium(IV) oxide (TiO2) and/or hyaluronic acid (HA) on glass plates after a low-temperature air plasma treatment. The surface free energy and its components were determined on the basis of advancing and receding contact angle measurements of water (W), formamide (F), and diiodomethane (DM). To estimate the total surface free energy (𝛾𝑠𝑡𝑜𝑡), the contact angle hysteresis (CAH) model was used, and the obtained data were compared with the results calculated from the Lifshitz-van der Waals/acid–base (LWAB) approach. It was found that the subphase components modify the surface of the phospholipid monolayer by changing the type and magnitude of interactions. They were reflected as significant differences in the obtained values of total surface free energy and its components. These findings can help in the development of composite materials, thereby expanding the spectrum of applications for chitosan, TiO2, and HA, as well as understanding the interactions between biomaterial and cell.
14
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Characterization of TiO2surface following the modification with silane coupling agents

61%
Jesionowski T., Siwińska-Stefańska K., Krysztafkiewicz A., Sójka-Ledakowicz J., Koprowska J., Pęczkowska B.
Polish Journal of Chemical Technology
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2007
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vol. 9
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issue 4
72-76
EN
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.
15
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Fowler-nordheim tunnelling in Au−TiO2−Ag film structures

61%
Aarik J., Bichevin V., Jõgi I., Käämbre H., Laan M., Sammelselg V.
Open Physics
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2004
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vol. 2
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issue 1
147-159
EN
I-V-characteristics have been measured for Au−TiO2−Ag structures with TiO2 layers of 30 and 180 nm thickness. The TiO2 films were grown by atomic layer deposition (ALD) technique. In the case of negative bias on the Au electrode, the conduction currents through TiO2 layers follow the Fowler-Nordheim formula for field emission over several orders of magnitude. The bulk of the currents may be attributed to tunnelling, seemingly through a Schottky barrier at the Au−TiO2 junction. In the case of reversed polarity the currents are also observed, but cannot be interpreted as tunnelling.
16
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Modelling particle deagglomeration in a batch homogenizer using full CFD and mechanistic models

61%
Krzosa R., Wojtas K., Golec J., Makowski Ł., Orciuch W., Adamek R., Krzosa R., Wojtas K., Golec J., Makowski Ł., Orciuch W., Adamek R.
Chemical and Process Engineering
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2021
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vol. 42
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issue 2
17
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Effect of calcination temperature on photocatalytic activity of TiO2. Photodecomposition of mono- and polyazo dyes in water

61%
Mozia S.
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EN
The presented studies have focused on the influence of TiO2 properties, such as crystalline phase, crystallite size and surface area, on the effectiveness of degradation of azo dyes in water under UV irradiation. Two monoazo dyes: Acid Red 18 (AR18, C20H11N2Na3O10S3) and Acid Yellow 36 (AY36, C18H14N3NaO3S), and one polyazo dye Direct Green 99 (DG99, C44H28N12Na4O14S4) were applied as model compounds. The photocatalysts were prepared from a crude titanium dioxide obtained directly from the production line (sulfate technology) at the Chemical Factory "Police" (Poland). The crude TiO2 was calcinated in air for 1-4h at the temperatures ranging from 600 to 800°C. The BET specific surface area of TiO2 decreased gradually with increasing the calcination temperature. The crude TiO2 exhibited specific surface area of 277 m2/g. In case of the catalysts heated at 600, 700 and 800°C the BET surface area amounted to 62.3-53.3, 33.4-26.8 and 8.9-8.3 m2/g, for the calcination time of 1-4h, respectively. The crystallite size of anatase increased with increasing heat treatment temperature and ranged from 19 to 53 nm, for the temperatures of 600-800°C, respectively. The catalysts annealed at 600 and 700°C contained primarily anatase phase (94-97%), whereas the photocatalysts heated at 800°C were composed mainly of rutile (97-99%). The highest effectiveness of azo dyes degradation was obtained in case of the photocatalyst calcinated for 1h at 700°C. The photocatalyst was composed mainly of anatase (97%) with crystallite size of 27 nm. The most effectively photodegraded was AR18, having the molecular weight of 640.4 g/mol. The most difficult to degrade was AY36 exhibiting the lowest molecular weight from all the dyes used (375.4 g/mol).
18
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Influence of calcination temperature on optical and structural properties of TiO2 thin films prepared by means of sol-gel and spin coating

51%
Tański T., Matysiak W., Kosmalska D., Lubos A.
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2018
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issue 2
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