scholarly journals TiO2 and N-TiO2 Sepiolite and Zeolite Composites for Photocatalytic Removal of Ofloxacin from Polluted Water

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 537 ◽  
Author(s):  
Michela Sturini ◽  
Federica Maraschi ◽  
Alice Cantalupi ◽  
Luca Pretali ◽  
Stefania Nicolis ◽  
...  
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Zeolite Catalysts ◽  
Polluted Water ◽  
X Ray Diffraction ◽  
Direct Photolysis ◽  
Drug Degradation ◽  
Particle Dimension ◽  
Photocatalytic Removal ◽  
Tio2 Support

TiO2 sepiolite and zeolite composites, as well the corresponding N-doped composites, synthesized through a sol–gel method, were tested for the photocatalytic degradation of a widespread fluoroquinolone antibiotic (ofloxacin) under environmental conditions. The catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) analyses. A complete drug degradation occurred in 10–15 min in the presence of both TiO2 sepiolite and zeolite catalysts, and in 20–30 min with the N-doped ones. Sepiolite proved to be a better TiO2 support compared to the most common zeolite both in terms of adsorption capacity and photocatalytic efficiency in pollutants degradation. The influence of nitrogen doping (red shift from 3.2 to 3.0 eV) was also investigated. Although it was blurred by a marked increase of the particle dimension and thus a decrease of the specific surface area of the doped catalysts, it allowed a faster drug removal than direct photolysis. The photochemical paths and photoproducts were investigated, too.

Visible-Light-Induced Photocatalytic Activity of Boron-Doped BiVO4

2014 ◽  
Vol 809-810 ◽  
pp. 890-894
Author(s):  
Dan Li ◽  
Lian Wei Shan ◽  
Gui Lin Wang ◽  
Li Min Dong ◽  
Wei Li ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Reflectance Spectroscopy ◽  
Scheelite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Doped

Boron-BiVO4 samples were synthesized by sol-gel method. They were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction. Photocatalytic activity of the obtained BiVO4 samples was investigated through degrading methylene blue (MB). The results reveal that boron-BiVO4 catalysts have monoclinic scheelite structure. The BiVO4 and Co-BiVO4 photocatalysts were responsive to visible light. Co-BiVO4 photocatalyst showed higher photocatalytic activity than pure BiVO4, resulting in the significantly improved efficiency of degradation of MB.

scholarly journals Improved Visible Light Photocatalytic Activity for TiO2Nanomaterials by Codoping with Zinc and Sulfur

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Qianzhi Xu ◽  
Xiuying Wang ◽  
Xiaoli Dong ◽  
Chun Ma ◽  
Xiufang Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sunlight Irradiation ◽  
X Ray ◽  
Transmission Electron ◽  
Photoinduced Charge

S/Zn codoped TiO2nanomaterials were synthesized by a sol-gel method. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the morphology, structure, and optical properties of the prepared samples. The introduction of Zn and S resulted in significant red shift of absorption edge for TiO2-based nanomaterials. The photocatalytic activity was evaluated by degrading reactive brilliant red X-3B solution under simulated sunlight irradiation. The results showed S/Zn codoped TiO2exhibited higher photocatalytic activity than pure TiO2and commercial P25, due to the photosynergistic effect of obvious visible light absorption, efficient separation of photoinduced charge carriers, and large surface area. Moreover, the content of Zn and S in the composites played important roles in photocatalytic activity of TiO2-based nanomaterials.

Nd@TiO2 Nanocomposite for Photocatalytic Inactivation of Escherichia coli

2020 ◽  
Vol 20 (3) ◽  
pp. 1447-1453 ◽  
Author(s):  
De-Shuai Zhen ◽  
Xiao-Hu Luo ◽  
De Yang ◽  
Hong-Tao Zou ◽  
Er-Hu Xiong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Sol Gel ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
E Coli ◽  
Simulated Solar Light ◽  
Solar Light Irradiation ◽  
Transmission Electron

In present work, a novel Nd@TiO2 Nanocomposite, synthesized successfully by a facile sol–gel method, reveals significant light-activated antibacterial activity. The X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) show the anatase phase and globular shape of Nd@TiO2. UV-vis diffuse reflectance spectroscopy and low temperature N2 adsorption (BET) indicate Nd0.02@TiO2 has the narrow band gap (3.0 eV) and a high specific surface area (121.1 m2·g-1). Furthermore, the prepared Nd@TiO2 exhibits unprecedented higher photocatalytic activity than P25 TiO2. In water, Nd@TiO2 has higher inactivation against Escherichia coli (E. coli) bacteria under simulated solar light irradiation 70 min than TiO2, and the highest antibacterial efficiency (91.5%) of E. coli was achieved on Nd0.02@TiO2.

The Influence of ZnO Components on the Photocatalytic Activity of Fe3O4-CuO-ZnO Nanocomposites

2015 ◽  
Vol 1123 ◽  
pp. 227-232 ◽  
Author(s):  
Iqriah Kalim Susanto ◽  
Ardiansyah Taufik ◽  
Rosari Saleh
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible

Nanocomposite Fe3O4-CuO-ZnO with different molar ratio of Fe3O4:CuO:ZnO were synthesized using sol-gel method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope, UV-visible diffuse reflectance spectroscopy and vibrating sample magnetometer. The characterization results manifested that the combination of Fe3O4, CuO and ZnO nanoparticles was successful. The photocatalytic activity of nanocomposite with the molar ratio of 1:1:5 was more effective in the degradation of methylene blue under UV light irradiation than pure Fe3O4, CuO, ZnO. The role of photoactive species involved in the photocatalytic reaction was studied and found that holes play the most important role in photodegradation of methylene blue.

Functionalization of Sol-Gel Zirconia Composites with Europium Complexes

2014 ◽  
Vol 69 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Nina Danchova ◽  
Stoyan Gutzov
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Reflectance Spectroscopy ◽  
Luminescence Spectroscopy ◽  
Quantum Yields ◽  
X Ray Diffraction ◽  
Europium Complexes ◽  
X Ray ◽  
Zirconia Composites

Different sol-gel strategies based on functionalization of ZrO2:Eu microparticles with 1,10- phenanthroline (phen) and incorporation of colloidal Eu(phen)2(NO3)3 into zirconia have been used to obtain hybrid sol-gel composites with controlled optical properties. The process leads to materials with quantum yields of about 48% monitoring the 615 nm emission line at 350 nm excitation. Excitation/ luminescence spectroscopy, diffuse reflectance spectroscopy and X-ray diffraction have been used to characterize the hybrid zirconia composites.

scholarly journals PHOTOCATALYTIC DEGRADATION OF PARAQUAT USING N-TiO2/SiO2 UNDER VISIBLE LIGHT

2018 ◽  
Vol 55 (4C) ◽  
pp. 277 ◽  
Author(s):  
Nguyen Thi Phuong Mai
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Organic Pollutant ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Illumination Time ◽  
X Ray

In the present paper, photocatalytic degradation of paraquat using N-TiO2/SiO2 with different molar ratio of titanium: nitrogen (Ti:N) under visible light was investigated. The catalyst was prepared via immersed SiO2 in N-TiO2. N-TiO2 was synthesized by sol-gel method.  The N-TiO2/SiO2 catalyst was characterized using X-ray diffraction, UV diffuse reflectance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy. The results from characterizations indicated that N-doped anatase TiO2 had a 20-25 nm size. Degradation of paraquat, at an initial concentration of 10 mg/L was determined by UV-Vis. Chemical oxygen demand (COD) was used for process performance. Based on the COD tests, the COD values in residual paraquat was lower than that in initial paraquat concentration after 8 hours illumination of visible light. Moreover, the experiment’s results indicated that 80% of paraquat was degraded within 8 h of illumination time. These results showed that N-TiO2/SiO2 with molar Ti:N=2:1 gives the highest degradation efficiency of paraquat under visible light. This catalyst was stable and reusable suggesting it can be applied to treat organic pollutant in water. 

scholarly journals Synthesis and Characterization of Lead Free Calcium Bismuth Titanate (Ca0.25Bi0.5 TiO3) Piezoelectric Ceramics

2019 ◽  
pp. 161-164
Keyword(s):  
Bismuth Titanate ◽  
Sol Gel ◽  
Piezoelectric Ceramics ◽  
Xrd Analysis ◽  
Free Calcium ◽  
X Ray Diffraction ◽  
Toxic Heavy Metals ◽  
Sem Images ◽  
Photocatalytic Removal

Bismuth layer-structured piezoelectric (BLSP) calcium bismuth titanate (Ca0.25Bi0.5TiO3) piezoelectric ceramics have been prepared via a conventional sol gel reaction method by mixing the desired chemicals in stoichiometric amounts. Calcium bismuth titanate (CBT) samples were characterized by means of XRD, SEM and FTIR spectroscopy. X-ray diffraction (XRD) analysis revealed that CBT ceramics exhibit a single phase orthorhombic structure. The SEM images confirm its morphological size ranging from 1.00 to 2.75 µm. FTIR analysis reveals that calcium bismuth titanate has been prepared successfully, and the ratio of calcium, bismuth and titania was found to be 0.25:0.50:1.00, respectively. The photocatalytic removal of Methylene Blue, cadmium (Cd2+) and other toxic heavy metals will be carried out using CBT materials.

Electrical and optical studies on tungsten-substituted bismuth molybdates

2020 ◽  
Vol 111 (7) ◽  
pp. 546-551
Author(s):  
Satish J. Naik ◽  
Puzy A. Pavaskar ◽  
Arun V. Salker
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rietveld Refinements ◽  
X Ray ◽  
Bismuth Molybdates ◽  
Infrared Techniques

Abstract This manuscript highlights the structural, electrical and optical properties of Bi2Mo1-xWxO6 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) compounds. These compounds were prepared employing the citrate sol-gel method. These compositions were characterized using thermo-gravimetric and differential scanning calorimetry, X-ray diffraction and infrared techniques. The Rietveld refinements of X-ray powder diffraction data determined and confirmed the crystal structure of the compositions. DC electrical conductivity indicated the conduction behaviour and diffuse reflectance spectroscopy confirmed the semiconducting nature of the compounds. Room temperature photoluminescence results exhibited two type of emission namely blue-green and green emission in the visible region.

Tailoring of Nanostructured ZnO-Fe3O4/TiO2 Composite Derived from MIL 125(Ti) for Efficient Photocatalytic Removal of Reactive Blue 21 from Aqueous Solutions

2021 ◽  
Author(s):  
Zahra Esania ◽  
Habibollah Younesi ◽  
Mohsen Nowrouzi
Keyword(s):  
Thermal Stability ◽  
Aqueous Solutions ◽  
Positive Impact ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Wastewater Treatment Process ◽  
Photocatalytic Removal ◽  
Successful Removal ◽  
Adsorption Desorption ◽  
Superparamagnetic Properties

Abstract A novel nanostructured ZnO-Fe3O4/TiO2 composite derived from MIL 125(Ti) was synthesized using mixed solvo-hydrothermal and sol-gel methods for efficient removal of Reactive Blue 21 (RB 21) from aqueous solutions under different conditions. The thermal stability, crystalline structure development, and superparamagnetic properties of the final composite were evaluated by thermogravimetric analysis, X-ray diffraction, and vibrating sample magnetometer instrument. The results approved that the as-synthesized ZnO-Fe3O4/TiO2 possessed a very high thermal stability up to ~ 900°C along with Zn-O, Ti-O, and Fe-O functional groups formation, which endowed superparamagnetic properties to this structure. A significant reduction of surface area from 603.96 (MIL 125(Ti)) to 51.48 m2/g (ZnO-Fe3O4/TiO2) was ascribed to the retailoring in construction, mesoporosity, and pore diameter development with a positive impact on the photocatalytic activities of the final product. The optimum condition with > 99% RB 21 removal was assigned at pH, initial concentration dye, catalyst dosage, and temperature of 2, 50 mg/L, 30 mg/100 mL, and 45°C, respectively. The thermodynamic studies disclosed that the adsorption process was nonspontaneous and endothermic. Furthermore, the synthesized ZnO-Fe3O4/TiO2 composite retained > 95% of its initial removal potential after five successive adsorption/desorption runs. Accordingly, ZnO-Fe3O4/TiO2 can be proposed for the successful removal of RB 21 in the wastewater treatment process.

Synthesis, Characterization and Comparative Study of TiO2 and ZnO Nanoparticles and their Application as a Photocatalysts for a Trichromatic Dye

2020 ◽  
Vol 5 (3) ◽  
pp. 252-268
Author(s):  
Meriem Kouhail ◽  
El Ahmadi Zakia ◽  
Benayada Abbes
Keyword(s):  
Zno Nanoparticles ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Sol Gel ◽  
Solar Irradiation ◽  
Operational Parameters ◽  
X Ray Diffraction ◽  
Aquatic Life ◽  
X Ray ◽  
Uv Visible

Background: The textile industrial effluents cause profound imbalances in ecosystems, when released into nature; dyes are oxidized by micro-organisms, resulting in a decrease in the dissolved oxygen, which is necessary for the aquatic life. For this reason, it is important to implement economic, efficient, and green methods ensuring both the discoloration and detoxification of water. Objective: TiO2 and ZnO nanoparticles were synthesized by sol-gel and precipitation methods, respectively. These two nanoparticles were used to compare photocatalytic degradation under UV and solar irradiation for three reactive azoic dyes (trichromatic): Reactive Bezactive Yellow (RBY), Reactive Bezactive Red (RBR), and Reactive Bezactive Blue (RBB). Methods: The structural, i.e., morphological surface properties of the synthesized photocatalysts were characterized by Fourier Transform Infrared, X-ray diffraction, UV-Visible diffuse reflectance spectroscopy, and Scanning Electron Microscopy. : X-ray diffraction shows that TiO2 has a tetragonal structure with an anatase form. The effects of some operational parameters, such as the amount of TiO2 and ZnO, initial dye concentration, dye mixtures, and pH, were examined. The progress of photodegradation reaction was monitored by UV-Visible spectroscopy for decolorization and by High-Performance Liquid Chromatography for degradation, and the efficiency of degradation was confirmed by Chemical Oxygen Demand measurement. Results: The dye degradation was found to be better in the presence of solar irradiation than under UV irradiation. The photocatalytic activity of ZnO was higher than TiO2 when used in its optimal conditions. Conclusion: The percentage of degradation of each dye is different, and the order of degradation of the three reactive dyes is as follows: RBY> RBR> RBB.

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