Wyniki wyszukiwania - BazTech

1

Synteza i zastosowanie modyfikowanych nanorurek TiO2

Górzyński Daniel, Nadolna Joanna, Kozak Magda, Mazierski Paweł

Wiadomości Chemiczne

|

2024

|

[Z] 78, 3-4

171--188

EN

Heterogeneous photocatalysis in the presence of semiconductor materials, especially TiO2, is increasingly studied due to its potential application in hydrogen generation, carbon dioxide conversion, and pollutant degradation. TiO2, known for its cost-effectiveness, stability, and safety, is particularly effective in its nanometric form, with nanotubes standing out for their structure that improves light absorption and charge carrier mobility. One approach to improve the properties of TiO2 for its application in photocatalytic processes involves its modification. Modifications of TiO2 nanotubes aim to reduce the rate of recombination of photogenerated charge carriers, increase photocatalytic activity in the UV range, extend its activity to the visible radiation range, and enhance reaction selectivity. Enhancing TiO2 photocatalytic efficiency involves modifications such as doping, creating heterojunctions, and introducing structural defects. The objective of this mini-review is to present selected methods of modifying TiO2 nanotubes obtained through anodic oxidation, leading to the enhancement of their photocatalytic properties.

2

Nanorurki TiO2 : synteza i zastosowanie

Mazierski Paweł

Wiadomości Chemiczne

|

2021

|

[Z] 75, 11-12

1195--1209

EN

Among all transition-metal oxides, TiO2 is one of the most studied compounds in materials science. Its tested in many applications such as biomedical, photochemical, electrical and environmental. Among these applications, maximization of the surface area to achieve the highest efficiency is crucial, thus nanostructured forms of TiO2 are very popular. TiO2 can be obtained in the form of zero-dimensional materials (nanoparticles), one-dimensional (nanowires, nanotubes), two-dimensional (nanosheets) and three-dimensional (nanospheres). Among these various nanostructured forms of TiO2, nanotubes are of the greatest interest due to high electron mobility, quantum confinement effects, a high specific surface area and very high mechanical strength. One-dimensional TiO2 nanotubes can be synthesized using the template, hydro/solvothermal, electrospinning and anodic oxidation methods, which leads to obtaining material in the form of a powder or a thin layer. Notwithstanding, ordered layers of TiO2 nanotubes obtained by anodic oxidation are particularly interesting in terms of application. This mini-review provides an overview of preparation methods of TiO2 nanotubes as well describes its most important applications with attention to key features.

3

Photocatalytic efficiencies of alternate heterogeneous catalysts: Iron modified minerals and semiconductors for removal of an azo dye from solutions

Yatmaz H. C., Sen U. D. K.

Environment Protection Engineering

|

2018

|

Vol. 44, nr 1

5--17

EN

Photocatalytic degradation of reactive dye solutions have been compared using two types of heterogeneous catalysts, i.e., semiconductors and iron modified clays. Decolorization and mineralization efficiencies of the catalysts were performed in a slurry batch reactor with UVA and UVC (365 and 254 nm, respectively) light sources using reactive azo dye solutions. Two natural minerals (zeolites and beidellites) modified with Fe3+, Fe2+and semiconductors (TiO2-P25 and ZnO) were used as photocatalysts. Iron modified minerals produced similar results compared to homogeneous photo-Fenton reactions under UVC radiation. Fe2+-beidellite and Fe3+-zeolite showed the best efficiency for dye removal with 98.5% at 75 min and 96.3% at 90 min, respectively, which is higher than the other iron modified minerals under UVA radiation. ZnO and TiO2 exhibited initial dye removal rates under UVA as 98.9% and 95.5% at 45 min, respectively. Mineralization efficiencies for TiO2, ZnO and Fe2+-beidellite, Fe3+ -zeolite under UVA were 86.2%, 74.5% and 76.9%, 67.8%, respectively. However mineral catalysts performed 99% dye removal rates within 15 min with respect to semiconductor catalyst values (over 97% within 45min) under UVC radiation. Mineral catalysts and TiO2 provided higher initial TOC removal rates as 92% in 60 min under UVC radiation.

4

Paracetamol and ibuprofen removal from aqueous solutions by ozonation and photochemical processes

Trousil V., Palarčík J., Blažková Z., Kořínková J., Machalický O., Cakl J.

Environment Protection Engineering

|

2018

|

Vol. 44, nr 4

159--175

EN

The comparative experimental study has been performed of removal of pharmaceuticals such as paracetamol and ibuprofen from aqueous solution by ozonation and photochemical degradation in several types of reactors. Ozone, oxygen, and hydrogen peroxide were used as oxidizing agents. Heterogeneous photocatalysis was carried out in the presence of anatase type TiO2 catalyst. To determine the amount of radiation emitted by the UV lamps and transferred into the reactor, chemical feroxioxalate actinometric experiments were performed. The degree of the pollutant removal was monitored by HPLC, COD, BOD5, and TOC. An ecotoxic biological test of process products with Parachlorella kessleri was also evaluated. The results indicate that the removal of both pharmaceuticals is most effective by heterogeneous photocatalysis. In the UV processes, the degradation rate increased considerably when H2O2 was added. However, the addition of peroxide into the ozonation system improved the ozonation only slightly. All products of the processes tested showed improved biodegradability according to the BOD5/COD ratio and low toxicity to Parachlorella kessleri.

5

Wpływ warunków procesowych na fotokatalityczny rozkład diklofenaku w środowisku wodnym

Kudlek E., Dudziak M., Bohdziewicz J.

Przemysł Chemiczny

|

2017

|

T. 96, nr 4

870--873

PL

Przedstawiono wyniki badania wpływu warunków procesowych heterogenicznej fotokatalizy (moc naświetlania, objętość reaktora, odczyn środowiska reakcji, obecność związków nieorganicznych) na rozkład diklofenaku, niesteroidowego leku przeciwbólowego i przeciwzapalnego.

EN

Diclofenac-contg. aq. solns. were subjected to photocatalytic decompn. by using UV lamps 15 or 150 W in the presence of TiO₂ as an air-oxidn. catalyst. The effect of reactor vol., pH of the reaction medium and the presence of inorg. micropollutants on the diclofenac degradn. was studied. The effectiveness of diclofenac oxidn. decreased with the increase in pH of aq. solns. The presence of NaCl, NaHCO₃ and Na₂SO₄ resulted in a decrease in the decompn. effectiveness. Furthermore, the diclofenac oxidn. by-products were formed, which could have a negative impact on living organisms.

6

Mathematical Kinetic Modelling and Representing Design Equation for a Packed Photoreactor with Immobilised TiO2-P25 Nanoparticles on Glass Beads in the Removal of C.I. Acid Orange 7

Sheidaei B., Behnajady M. A.

Chemical and Process Engineering

|

2015

|

Vol. 36, nr 2

125--133

EN

In this work, a design equation was presented for a batch-recirculated photoreactor composed of a packed bed reactor (PBR) with immobilised TiO2-P25 nanoparticle thin films on glass beads, and a continuous-flow stirred tank (CFST). The photoreactor was studied in order to remove C.I. Acid Orange 7 (AO7), a monoazo anionic dye from textile industry, by means of UV/TiO2 process. The effect of different operational parameters such as the initial concentration of contaminant, the volume of solution in CFST, the volumetric flow rate of liquid, and the power of light source in the removal efficiency were examined. A rate equation for the removal of AO7 is obtained by mathematical kinetic modelling. The results of reaction kinetic analysis indicate the conformity of removal kinetics with Langmuir-Hinshelwood model (kL-H = 0.74 mg L-1 min-1, Kads = 0.081 mg-1 L). The represented design equation obtained from mathematical kinetic modelling can properly predict the removal rate constant of the contaminant under different operational conditions (R2 = 0.963). Thus the calculated and experimental results are in good agreement with each other.

7

Fotokataliza w oczyszczaniu i dezynfekcji wody. Część . III, Zastosowanie w dezynfekcji wody i ścieków

Bodzek M., Rajca M.

Technologia Wody

|

2014

|

Nr 1 (33)

30--40

PL

W ostatnich latach ukazała się ogromna ilość prac na temat procesu fotokatalizy (heterogenicznej i homogenicznej), zaliczanych do specyficznych rodzajów technik utleniania, definiowanych, jako zaawansowane procesy utleniania (AOPs). Artykuł podaje stan wiedzy na temat wykorzystania procesów fotokatalizy Ti02 i foto Fentona, w tym promieni słonecznych, do unieszkodliwienia mikroorganizmów występujących w wodzie i ściekach. Praca podsumowuje również istniejące dane na temat właściwości cyjanotoksyn, ich powstawanie w środowisku, skuteczne fotokatalityczne usuwanie z wód naturalnych.

EN

In recent years, there has been a tremendous amount of research and development in the area of photocataly¬sis (heterogeneous and homogeneous), a process included in a special class of oxidation techniques defined as Advanced Oxidation Processes (AOPs). This paper reviews the use of TiOa photocatalysis and photo-Fenton processes, in this solar photocatalysis, to inactivate microorganisms present in water and wastewater. This review summarizes also the existing data on characteristics of the cyanotoxins, their productions in environment and photocatalvtic effective treatment processes to remove these toxins from natural water.

8

Fotokataliza w oczyszczaniu i dezynfekcji wody. Cz. IV, Zastosowanie w odnowie wody

Bodzek M., Rajca M.

Technologia Wody

|

2014

|

Nr 4 (36)

24--33

PL

Ścieki są od dawna postrzegane jako wiarygodne źródło recyklingu dla zaopatrzenia w wodę w regionach poważnie odczuwających niedobory wody. Jednakże, ścieki zawierają zanieczyszczenia organiczne i nieorganiczne oraz mikroorganizmy chorobotwórcze. Aby woda zużyta mogła być zawrócona i ponownie wykorzystana w praktyce, ścieki muszą zostać poddane szeregu procesom oczyszczania, aż do uzyskania jakości bezpiecznej do wielokrotnego użytku. Zaawansowane procesy utleniania, filtracja i technologia membranowa są powszechnie stosowane w zakładach oczyszczania ścieków i odnowy wody. Zastosowanie fotokatalizy półprzewodnikowej w oczyszczaniu ścieków cieszy się coraz większym zainteresowaniem ze względu na pełną mineralizację materii organicznej. W pracy przedstawiono możliwości zastosowania fotokatalizy w odnowie wody ze ścieków biologicznie oczyszczonych i tzw. wód szarych, pochodzących z gospodarstw domowych i zakładów usługowych.

EN

Wastewaters have long been seen as a reliable source for recycling water supply in many regions seriously affected by water shortages. However, the effluents contain a variety of organic and inorganic pollutants and pathogenic micro-organisms. If used water maybe returned and reused in practice, the effluent must undergo a series of treatment processes, so as to produce quality safe for reuse. Advanced oxidation processes, filtration and membrane technology are widely used in wastewater treatment and water renovation plants. Application of semiconductor photocatalytic in sewage treatment has been of increasing interest due to the complete mineralization of organic matter. This paper reviews ability of application of the photo-catalysis process in water renovation from biologically treated sewage effluent and from so called “gray waters” coming from households and service establishments.

9

Preparation of ag/cu-doped titanium (iv) oxide nanoparticles in w/o microemulsion

Zielińska-Jurek A., Walicka M., Tadajewska A., Łącka I., Gazda M., Zaleska A.

Physicochemical Problems of Mineral Processing

|

2010

|

Vol. 45

113-126

EN

The Cu-TiO2 and Ag/Cu-TiO2 nanoparticles have been prepared using a water-in-oil microemulsion system of water/AOT/cyclohexane. The photocatalytic activity of the catalysts was estimated by measuring the decomposition rate of phenol in 0.21 mM aqueous solution under visible light irradiation. The bioactivity of Ag/Cu-doped titanium (IV) oxide nanocomposites was estimated using bacteria Escherichia coli and Staphylococcus aureus, yeast Saccharomyces cerevisiae and pathogenic fungi belonging to Candida family. The photocatalysts' characteristics by X-ray diffraction, BET surface area measurements, Scanning Electron Microscopy (SEM) energy dispersive spectroscopy (EDS) analysis showed that a sample with the highest photo- and bioactivity had anatase structure, about 190 m2/g specific surface area, absorbed light for ?>400 nm and contained 1.45 mass % of silver, 1.40 mass % of copper and 59.4 mass % of Ti.

10

Characteristics of doped-TiO2 photocatalysts

Zaleska A.

Physicochemical Problems of Mineral Processing

|

2008

|

Vol. 42

213-224

EN

Titanium dioxide represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. TiO2 shows relatively high reactivity and chemical stability under ultraviolet light (λ<387nm), whose energy exceeds the band gap of 3.3 eV in the anatase crystalline phase. The development of photocatalysts exhibiting high reactivity under visible light (λ>380nm) should allow the main part of the solar spectrum, even under poor illumination of interior lighting, to be used. In this work the influence of TiO2 structure on visible light photoactivity and novel photocatalysts doped with sulfur, nitrogen, boron and carbon are presented. The photocatalytic activity of obtained powders was referred to dopant chemical form, crystalline structure, crystallite size, surface area and preparation method.

PL

Fotokatalityczne właściwości TiO2 wykorzystywane są między innymi do eliminacji substancji organicznych z fazy gazowej i ciekłej oraz w samooczyszczaniu powierzchni. Tlenek tytanu (IV) absorbuje prawie wyłącznie promieniowanie UV, dlatego podczas fotokatalizy wykorzystać można zaledwie od 3 do 5 % promieniowania słonecznego. Zatem otrzymanie półprzewodnika tytanowego nowej generacji aktywnego w zakresie promieniowania widzialnego (λ>400 nm), znacząco rozszerzyłoby możliwości aplikacyjne fotokatalizy heterogenicznej w ochronie środowiska, przez wykorzystanie głównej części spektrum światła słonecznego lub zastosowanie źródła światła o mniejszym natężeniu promieniowania. W niniejszej pracy omówiono nowe fotokatalizatory aktywne pod wpływem światła widzialnego, otrzymane poprzez modyfikację TiO2 związkami siarki, azotu, boru oraz węgla. Fotoaktywność otrzymanych fotokatalizatorów została odniesiona do charakteru chemicznego wprowadzonej domieszki, struktury krystalicznej, wielkości krystalitów, powierzchni właściwej fotokatalizatora oraz metody otrzymywania.