Effect of Heat Treatment on the Micro-Structural, Crystallinity and Photocatalytic Properties of Hydrothermally Prepared Titanate Nanowires

2016 ◽  
Vol 1133 ◽  
pp. 13-17
Author(s):  
Mohamad Siti Mariam ◽  
A.B. Siti Najihah ◽  
A.Z. Zuhana ◽  
M. Abd Kadir
Keyword(s):  
Aqueous Solution ◽  
Uv Light ◽  
Irradiation Time ◽  
Anatase Phase ◽  
Hydrothermal Process ◽  
Sodium Titanate ◽  
Xrd Analysis ◽  
Sample Heat ◽  
Heat Treated ◽  
Titanate Nanowires

Titanate nanowires were synthesised by hydrothermal process in 10M NaOH aqueous solution at 200oC for 24h. The samples were washed repeatedly in HCl aq. solution and deionized water until pH ~7. Subsequently, the samples were heat-treated at 400-850°C in air for 2h. The X-ray diffraction (XRD) analysis of the sample heat-treated at 800°C showed the crystalline structure of sodium titanate (Na2Ti6O13 ), while the presence of anatase phase was detected from the sample heat-treated at 850°C. Wire-like morphology of the synthesized sample was observed using FE-SEM. The photocatalytic activity of the samples heat-treated at 600,800, 850°C and 900°C was investigated by measuring the degradation of methylene blue (MB) in aqueous solution under UV-light irradiation and more than 90% of the dye was efficiently degraded by the sample heat-treated at 850°C within 45 minutes irradiation time as compared to other tested samples.

Synthesis of ZnO Flower-Like Nanostructures on GaN Epitaxial Layer by Hydrothermal Process

2007 ◽  
Vol 124-126 ◽  
pp. 555-558 ◽  
Author(s):  
Jae Min Jang ◽  
Sung Hak Yi ◽  
Seung Kyu Choi ◽  
Jeong A Kim ◽  
Woo Gwang Jung
Keyword(s):  
Aqueous Solution ◽  
Hydrothermal Synthesis ◽  
Epitaxial Layer ◽  
Hydrothermal Process ◽  
Xrd Analysis ◽  
Zno Nanostructures ◽  
Single Crystalline ◽  
Zno Nanostructure

3D type flower-like ZnO nanostructure is fabricated on GaN epitaxial layer by hydrothermal synthesis. The formation of ZnO nanostructures is controlled dominantly by pH of the aqueous solution. The microstructure of flower-like ZnO nanostructure was examined by FE-SEM, XRD and FE-TEM. It is found that the shape of ZnO nanostructures are likely flower and chestnut bur shapes. FE-TEM and XRD analysis shows that ZnO nanostructures are single crystalline. Some discussion is made on the mechanism of ZnO growth in solutions with different pH.

Magnetic field assisted photocatalytic degradation of organic dyes in the presence of Ag/TiO2 coated composite

2013 ◽  
Vol 67 (4) ◽  
pp. 722-728 ◽  
Author(s):  
Jian Wang ◽  
Jingqun Gao ◽  
Jun Wang ◽  
Yu Zhai ◽  
Zhongxing Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Rotational Speed ◽  
Organic Dyes ◽  
Dye Degradation ◽  
Uv Light ◽  
Irradiation Time ◽  
Sol Gel ◽  
Heat Treated

Ag/TiO2 coated composite was prepared via sol-gel method in order to elucidate its application in magnetic field assisted photocatalytic degradation of dyes. Through the degradation of organic dyes, the key influences such as Ag amount, heat-treated temperature and time on the photocatalytic activity of Ag/TiO2, as well as UV irradiation time, rotational speed, dye concentration and magnetic sheet number on the photocatalytic degradation were studied. Results showed that the Ag/TiO2 with 25 wt% Ag content heat-treated at 550 °C for 60 min has the best photocatalytic activity. With the increase of UV light irradiation time, rotational speed and magnetic sheet number, the degradation rate is improved. Different dye degradation proved that the method could universally be used.

scholarly journals Removal of Pb (II) Ions in The Aqueous Solution by Photo-Fenton Method

2019 ◽  
Vol 21 (2) ◽  
pp. 180-186 ◽  
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Uv Light ◽  
Irradiation Time ◽  
Oxidation Mechanism ◽  
Operating Parameters ◽  
Oh Radicals ◽  
Oh Radical ◽  
Fenton Process ◽  
Batch Technique

<p>Photo-Fenton for decreasing concentration of Pb(II) ions in the aqueous solution is systematically studied. The photo-Fenton process was carried out by batch technique, under UV light. The influences of process operating parameters were evaluated. The results of the research demonstrated that by photo-Fenton process, the concentration of Pb(II) ions in the aqueous solution can be decreased, that may be through oxidation mechanism by OH radicals. The decrease is found to be controlled by Fe2+ and H2O2 concentrations, as well as by the pH and the irradiation time. For 20 mg/L of Pb(II) in the 100 mL solution, the optimum condition of the oxidation is obtained to be 10 mmole/L of Fe2+, 200 mmole/L of H2O2, pH 3, and 90 min of the reaction time. It is also confirmed that the oxidation of Pb (II) by OH radical has formed the undissolved PbO2, that is less toxic and easier to be handled.</p>

scholarly journals Photodegradation of some brominated and phenolic micropollutants in raw hospital wastewater with CeO2 and TiO2 nanoparticles

2017 ◽  
Vol 76 (10) ◽  
pp. 2603-2622 ◽  
Author(s):  
Delia Teresa Sponza ◽  
Gökçe Güney
Keyword(s):  
Surface Area ◽  
Uv Light ◽  
Irradiation Time ◽  
Anatase Phase ◽  
Hospital Wastewater ◽  
Nano Tio2 ◽  
Experimental Conditions ◽  
Light Power ◽  
Sequential Treatments ◽  
Average Size

Abstract In this study, the degradations of 2,3,4,5,6-pentabromotoluene (PBT), 2,3,4,5,6-pentabromoethyl benzene (PBEB), triclosan (TCS) and gemfibrozil (GFZ) in raw hospital wastewater were investigated with cerium (IV) oxide and titanium (IV) oxide nanoparticles considering the mechanisms of adsorption, photolysis, and photocatalysis with UV-C lamps. The effects of nano-CeO2 and nano-TiO2 concentrations, irradiation times, UV light powers and hospital wastewater pH on the photodegradation yields of micropollutants namely PBT, PBEB, TCS and GFZ were investigated throughout photocatalysis. The nano-TiO2 produced had an anatase phase with crystalline shape with a surface area of 205 m2 g−1 and an average size of 11.50 nm. The CeO2 nanoparticles had a spherical shape with a higher surface area (302 m2 g−1) than that of TiO2 and a lower average size (8.11 nm). It was found that the removals of PBT, PBEB, TCS and GFZ with adsorption (5.7%–17.1%) and photolysis (9.0%–15.9%) were not significant for both nanoparticles. The photodegradation of PBT (92%), PBEB (90%), TCS (97%) and GFZ (95%) with nano-CeO2 gave better results than nano-TiO2 (90%, 87%, 94% and 93% for PBT, PBEB, TCS and GFZ, respectively) under optimum experimental conditions (0.50 g L−1 nano-CeO2, 45 min irradiation time, 25 °C temperature, pH = 8.50, 210 W UV light power). Both nanoparticles were reused effectively after photo-removals of the micropollutants from the hospital wastewater. The lowest photodegradation yields were 80%, 78%, 75% and 74% for TCS, GFZ, PBT and PBEB, respectively, with nano-TiO2 after six sequential treatments. The lowest photodegradation yields were 86%, 83%, 80% and 79% for the same micropollutants, respectively, with nano-CeO2 after six sequential treatments. The cost to treat 1 m3 raw hospital wastewater were 8.70 € and 2.28 €, for the photocatalytic treatments with nano-TiO2 and nano-CeO2, respectively.

Nanocrystallinity Enhancement of TiO2 Nanotubes by Post-Hydrothermal Treatment

2011 ◽  
Vol 277 ◽  
pp. 90-99 ◽  
Author(s):  
Akhmad Herman Yuwono ◽  
Nofrijon Sofyan ◽  
Indriana Kartini ◽  
Alfian Ferdiansyah ◽  
Tego Hadi Pujianto
Keyword(s):  
Hydrothermal Treatment ◽  
Optical Characteristic ◽  
Hydrothermal Process ◽  
Sodium Titanate ◽  
Xrd Analysis ◽  
Band Gap Energy ◽  
Crystallite Growth ◽  
Hydrothermal Temperature ◽  
Gap Energy ◽  
Vis Spectroscopy

In the present research, a modified post-hydrothermal treatment with different temperature of 80-150°C has been applied on as-annealed TiO2 nanotubes derived from conventional hydrothermal process. The treatment has two-fold objectives, i.e. enhancing the nanocrystallinity of anatase TiO2, and at the same time maintaining the integrity of nanotube structures. The resulting TiO2 nanotubes were characterized by using XRD and UV-Vis spectroscopy. The XRD analysis revealed that the as dried TiO2 nanotubes contain combined crystalline structures of sodium-titanate and anatase. It was also found that by increasing the post-hydrothermal temperature from 80 to 150°C, the nanocrystallinity of nanotubes enhances as indicated by increasing the crystallite size of anatase TiO2 from 6.93 to 7.81 nm. The anatase crystallite growth affected the optical characteristic of nanotubes, as represented with the reduction of the band gap energy, Eg from 3.75 to 3.67 eV by using Kubelka-Munk analysis for the obtained UV-Vis reflectance spectra. TEM observation confirms that the integrity of nanotubes structure can be well-maintained upon post-hydrothermal treatment.

scholarly journals Comparing Photocatalytic Activity of ZnO and Nanospherical ZnO/Bentonite Catalyst: Preparation, Structural Characterization and their Photocatalytic Performances using Oxytetracycline Antibiotic in Aqueous Solution

2018 ◽  
Vol 62 (1) ◽  
Author(s):  
Ali İmran VAİZOĞULLAR
Keyword(s):  
Aqueous Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Xrd Analysis ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
One Step

<strong></strong>Photocatalytic degradation of Oxytetracycline (OTC) in aqueous solution was performed using pure ZnO and ZnO/Bent composites. Both catalysts were synthesized trough a simple one-step chemical precipitation method. The prepared samples were characterized using SEM-EDAX and XRD analysis. Due to the immobilization of ZnO nanospheres upon bentonite surface, 25.67 m<sup>2</sup> g<sup>-1</sup> of specific surface area was obtained for the ZnO/Bent which lower than the specific surface area of the raw bentonite (112.25 m<sup>2</sup> g<sup>-1</sup>). ZnO/Bent catalyst showed the best photocatalytic performance than ZnO for OTC degradation under UV light.

Immobilization of ZnO Suspension on Glass Substrate to Remove Filtration During the Removal of Remazol Red R from Aqueous Solution

2016 ◽  
Vol 12 (6) ◽  
pp. 4127-4133
Author(s):  
Nazmul Kayes ◽  
Jalil Miah ◽  
Md. Obaidullah ◽  
Akter Hossain ◽  
Mufazzal Hossain
Keyword(s):  
Aqueous Solution ◽  
Glass Substrate ◽  
Uv Light ◽  
Aqueous Suspension ◽  
Light Irradiation ◽  
Zno Films ◽  
Light Sources ◽  
Zno Film ◽  
Semiconductor Oxides ◽  
Remazol Red

Photodegradation of textile dyes in the presence of an aqueous suspension of semiconductor oxides has been of growing interest. Although this method of destruction of dyes is efficient, the main obstacle of applying this technique in the industry is the time and cost involving separation of oxides from an aqueous suspension. In this research, an attempted was made to develop ZnO films on a glass substrate by simple immobilization method for the adsorption and photodegradation of a typical dye, Remazol Red R (RRR) from aqueous solution. Adsorption and photodegradation of  RRR were performed in the presence of glass supported ZnO film. Photodegradation of the dye was carried out by varying different parameters such as the catalyst dosage, initial concentrations of RRR, and light sources. The percentage of adsorption as well as photodegradation increased with the amount of ZnO, reaches a maximum and then decreased. Maximum degradation has been found under solar light irradiation as compared to UV-light irradiation. Removal efficiency was also found to be influenced by the pre-sonication of ZnO suspension.

Facile Preparation of Nanoporous SnO2 for Application in Photodegradation of Methylene Blue

2011 ◽  
Vol 194-196 ◽  
pp. 385-388
Author(s):  
Hong Juan Wang ◽  
Feng Qiang Sun ◽  
Ming Zhong Ren ◽  
Qing Wei Guo
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
High Photocatalytic Activity ◽  
N2 Adsorption ◽  
Photochemical Method ◽  
Degussa P25 ◽  
Adsorption Desorption

Nanoporous SnO2with high photocatalytic activity has been successfully prepared by a photochemical method, using SnCl2aqueous solution as a precursor. The as-synthesized sample was characterized by XRD, N2 adsorption-desorption and UV-vis. The photocatalytic activity of the sample was evaluated by degrading methylene blue (MB) aqueous solution under the UV light source and was compared with that of the commercial titania (Degussa P25). The results showed that the produced SnO2can degrade MB solution quickly and has comparative photocatalytic performance with P25 for degrading MB. This facile method supplies an effective way to prepare SnO2photocatalyst.

Preparation, Characterization and Photocatalytic Activity of F, Fe-Codoped Nano-TiO2

2013 ◽  
Vol 448-453 ◽  
pp. 169-173
Author(s):  
Chun Yan Yan ◽  
Wen Tao Yi
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Neutral Red ◽  
Reaction Model ◽  
X Ray Diffraction ◽  
Pseudo First Order Reaction ◽  
Adsorption Desorption ◽  
Desorption Method

Pure and F, Fe-codoped TiO2 were prepared by sol-hydrothermal process, in which titanium (IV) n-butoxide, Fe (NO3)2·6H2O and NH4F were used as precursors. And the samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and N2 adsorption-desorption method. The results showed that the F, Fe-codoped samples were principally single-phase anatase structures, and the particles possessed higher BET area than that of pure TiO2. The photocatalytic activity and reusability of the catalysts under UV light (365nm) was investigated with neutral red as the model compound. The results showed that F (2.0%), Fe (4.0%) codoped TiO2 had the highest photocatalytic activity among all as-prepared samples. The kinetic study showed that this photocatalytic process coincided with the Langmuir-Hinshelwood (L-H) pseudo first order reaction model.

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