Optimized photocatalytic degradation of caffeic acid by sol–gel TiO2

TiO2 anatase powder was prepared by means of the sol–gel method with titanium(IV) butoxide as precursor. The formation of a tetragonal crystal structure of TiO2 anatase at 500 °C was confirmed by X-ray powder diffraction. The characterization of the samples synthesized was complemented by scanning electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, nitrogen adsorption–desorption isotherms (Brunauer–Emmett–Teller) and diffuse reflectance spectroscopy. The photocatalytic activity of the TiO2 anatase powder was evaluated in the degradation of caffeic acid in aqueous solution under ultraviolet radiation. A central composite circumscribed design was used to assess the weight of the experimental variables, pH and amount of catalyst in the percentage of caffeic acid degraded and the optimal conditions. The optimized conditions were found to be pH = 5.2 and a load of TiO2 of 1.1 g L−1. Under these conditions more than 90% of caffeic acid degradation was achieved after 30 min of lamp irradiation. At this time the mineralization reached was almost 60%.

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Preparation of Fe3O4/TiO2 magnetic mesoporous composites for photocatalytic degradation of organic pollutants

Water Science & Technology ◽

10.2166/wst.2017.002 ◽

2017 ◽

Vol 75 (7) ◽

pp. 1523-1528 ◽

Cited By ~ 12

Author(s):

Hongfeng Zhang ◽

Xiu He ◽

Weiwei Zhao ◽

Yu Peng ◽

Donglan Sun ◽

...

Keyword(s):

Diffuse Reflectance ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Nitrogen Adsorption ◽

Magnetic Composite ◽

X Ray Diffraction ◽

X Ray ◽

Mesoporous Composites ◽

Uv Lamp ◽

Adsorption Desorption

Fe3O4/TiO2 magnetic mesoporous composites were synthesized through a sol-gel method with tetra-n-butyl titanate as precursor and surfactant P123 as template. The as-prepared Fe3O4/TiO2 composites were characterized by X-ray diffraction, diffuse reflectance spectroscopy, nitrogen adsorption-desorption isotherm and pore size distribution. The as-synthesized products were applied as photocatalysis for the degradation of Acid Black ATT and tannery wastewater under UV lamp irradiation. Fe3O4/TiO2-8 composites containing Fe3O4 of 8 wt% were selected as model catalysts. The optimal catalyst dosage was 3 g/L in this photocalytic system. The magnetic Fe3O4/TiO2 composites possessed good photocatalytic stability and durability. This approach may provide a platform to prepare a magnetic composite to optimize the catalytic ability.

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Evaluation of Hydrocalumite-Like Compounds as Catalyst Precursors in the Photodegradation of 2,4-Dichlorophenoxyacetic Acid

International Journal of Photoenergy ◽

10.1155/2016/5256941 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 3

Author(s):

Manuel Sánchez-Cantú ◽

Clara Barcelos-Santiago ◽

Claudia M. Gomez ◽

Esthela Ramos-Ramírez ◽

Ma. de Lourdes Ruiz Peralta ◽

...

Keyword(s):

Diffuse Reflectance ◽

Diffuse Reflectance Spectroscopy ◽

Nitrogen Adsorption ◽

Dichlorophenoxyacetic Acid ◽

X Ray ◽

2,4 Dichlorophenoxyacetic Acid ◽

Adsorption Desorption ◽

Oxide Ions ◽

Environmentally Friendly Method ◽

Simple Economic

Three hydrocalumite-like compounds in a Ca/Al ratio of 2 containing nitrate and acetate anions in the interlaminar region were prepared by a simple, economic, and environmentally friendly method. The solids were characterized by X-ray powder diffraction (XRD), thermogravimetric (TG) analysis, nitrogen adsorption-desorption at −196°C, scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and UV-Vis Diffuse Reflectance Spectroscopy (DRS). The catalytic activity of the calcined solids at 700°C was tested in the photodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) where 57% degradation of 2,4-D (40 ppm) and a mineralization percentage of 60% were accomplished within 150 minutes. The photocatalytic properties were attributed to mayenite hydration, since the oxide ions in the cages are capable of reacting with water to form hydroxide anions capable of breaking down the 2,4-D molecules.

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Enhanced Photocatalytic Removal of Cyanotoxins by Al-Doped ZnO Nanoparticles with Visible-LED Irradiation

Toxins ◽

10.3390/toxins13010066 ◽

2021 ◽

Vol 13 (1) ◽

pp. 66

Author(s):

Majdi Benamara ◽

Elvira Gómez ◽

Ramzi Dhahri ◽

Albert Serrà

Keyword(s):

Photocatalytic Degradation ◽

Diffuse Reflectance Spectroscopy ◽

Degradation Kinetics ◽

Sol Gel ◽

Nitrogen Adsorption ◽

Zno Nanoparticle ◽

Al Content ◽

Doped Zno ◽

Adsorption Desorption ◽

Neutral Conditions

The ZnO-based visible-LED photocatalytic degradation and mineralization of two typical cyanotoxins, microcystin-LR (MC-LR), and anatoxin-A were examined. Al-doped ZnO nanoparticle photocatalysts, in Al:Zn ratios between 0 and 5 at.%, were prepared via sol-gel method and exhaustively characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption isotherms. With both cyanotoxins, increasing the Al content enhances the degradation kinetics, hence the use of nanoparticles with 5 at.% Al content (A5ZO). The dosage affected both cyanotoxins similarly, and the photocatalytic degradation kinetics improved with photocatalyst concentrations between 0.5 and 1.0 g L−1. Nevertheless, the pH study revealed that the chemical state of a species decisively facilitates the mutual interaction of cyanotoxin and photocatalysts. A5ZO nanoparticles achieved better outcomes than other photocatalysts to date, and after 180 min, the mineralization of anatoxin-A was virtually complete in weak alkaline medium, whereas only 45% of MC-LR was in neutral conditions. Moreover, photocatalyst reusability is clear for anatoxin-A, but it is adversely affected for MC-LR.

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Synthesis of Ag-TiO2/perlite composite for the photodegradation of methylene blue under solar light irradiation

Vietnam Journal of Catalysis and Adsorption ◽

10.51316/jca.2020.068 ◽

2020 ◽

Vol 9 (4) ◽

pp. 42-48

Author(s):

Nui Pham Xuan ◽

Hoa Nguyen Thi ◽

Tien Nguyen Trung ◽

Tai Le Huu ◽

Thi Tran Thi Van

Keyword(s):

Methylene Blue ◽

Photocatalytic Activity ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Nitrogen Adsorption ◽

Band Gap Energy ◽

Light Irradiation ◽

Solar Light ◽

Solar Light Irradiation ◽

Adsorption Desorption

In this research, photocatalytic materials of TiO2, Ag-TiO2, Ag-TiO2/perlite were synthesized by the sol-gel method. By combining the photocatalytic activity between Ag-TiO2 and Perlite mineral, the Ag-TiO2/perlite composite has overcome the disadvantages of pristine TiO2, such as high band gap energy, low light utilization and easy recombination of electrons and holes. The synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity of the samples was tested for degradation of methylene blue (MB) under solar light irradiation. Photodegradation studies revealed a 95% removal of MB dye via the synthesized Ag-TiO2/perlite after 150 min of irradiation. Reusability of this hybrid photocatalyst system was tested and only a 3% decrease was observed after four cycles.

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The Synthesis and Photocatalytic Performance of Samarium Doped Mesoporous Titania

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.876.15 ◽

2018 ◽

Vol 876 ◽

pp. 15-19

Author(s):

Jian Wen Shi ◽

Dan Dan Ma ◽

Ya Jun Zou

Keyword(s):

Diffuse Reflectance ◽

Photocatalytic Performance ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Nitrogen Adsorption ◽

Reflectance Spectroscopy ◽

Mesoporous Titania ◽

X Ray Diffraction ◽

Structure Directing Agent ◽

X Ray

The meso-porous TiO2 and Sm-doped meso-porous TiO2 were synthesized by a sol-gel method. Polyethylene glycol, with different added content, was added as a structure-directing agent. The prepared meso-porous TiO2 was characterized by nitrogen adsorption, X-ray diffraction and ultraviolet-visible diffuse reflectance spectroscopy, and the photocatalytic performance was evaluated by the decomposition of methyl orange. The results revealed that PEG plays a key role in creating porous structure during the heat-treatment. The photocatalytic performance of TiO2 is improved by adding proper content PEG, and Sm-doping can further promote the photocatalytic performance.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.809-810.890 ◽

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.

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Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.230 ◽

2013 ◽

Vol 284-287 ◽

pp. 230-234

Author(s):

Yu Jen Chou ◽

Chi Jen Shih ◽

Shao Ju Shih

Keyword(s):

Surface Area ◽

Calcination Temperature ◽

High Surface ◽

Sol Gel ◽

High Surface Area ◽

Nitrogen Adsorption ◽

Bioactive Glasses ◽

Transmission Electron ◽

Sol Gel Process ◽

Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

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Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽

10.3390/ma12111771 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1771 ◽

Cited By ~ 2

Author(s):

Stefan Neatu ◽

Mihaela M. Trandafir ◽

Adelina Stănoiu ◽

Ovidiu G. Florea ◽

Cristian E. Simion ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalytic Combustion ◽

Mixed Oxides ◽

Sol Gel ◽

Nitrogen Adsorption ◽

X Ray Diffraction ◽

X Ray ◽

Temperature Programmed ◽

Catalytic Combustion Of Methane ◽

Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

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Effectiveness of photodecomposition of rhodamine B and malachite green upon coupled tricomponent TiO2(Anatase-Rutile)/ZnO nanocomposite

Acta Chimica Slovaca ◽

10.2478/acs-2013-0038 ◽

2013 ◽

Vol 6 (2) ◽

pp. 245-255 ◽

Cited By ~ 11

Author(s):

Dongfang Zhang

Keyword(s):

Malachite Green ◽

Rhodamine B ◽

Active Sites ◽

Diffuse Reflectance Spectroscopy ◽

Organic Dyes ◽

Synergistic Effects ◽

Sol Gel ◽

Photocatalytic Decomposition ◽

Photoluminescence Intensity ◽

Tio2 Anatase

Abstract In this study, mixed phase ZnO-TiO2 nanocomposite consisting of hexagonal ZnO and anatase/rutile TiO2 has been synthesized via sol-gel process.The physical and photochemical properties of samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminscience spectra (PL) and and photocurrent action spectra techniques. In the case of minerlization of rhodamine B (RhB) and malachite green (MG) dyes, the coupled ZnO-TiO2 nanocomposite with the suitable band structure and the lowest photoluminescence intensity showed the best photodecolorization activity. Synergistic effects between the two oxides for photocatalytic decomposition of RhB and MG are proposed to elucidate the decolorization mechanism. The lifetime of electrons and holes was prolonged in the ZnO-anatase/rutile multiple-component system, which can enhance the light harvest and the ability of generating photo-induced electron-hole pairs of active sites, and the favorable electron-transfer properties in the coupled ZnO-TiO2 nanocomposite. Therefore, the as-prepared ZnO-TiO2 nanocomposite showed an excellent efficiency towards the removal of aqueous organic dyes and it is of certain significance for environmental photocatalysis.

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VISIBLE LIGHT ACTIVE Cu2+/TiO2 NANOCATALYST FOR DEGRADATION OF DICHLORVOS

International Journal of Nanoscience ◽

10.1142/s0219581x12500305 ◽

2012 ◽

Vol 11 (05) ◽

pp. 1250030 ◽

Cited By ~ 3

Author(s):

TESHOME ABDO SEGNE ◽

SIVA RAO TIRUKKOVALLURI ◽

SUBRAHMANYAM CHALLAPALLI

Keyword(s):

Catalytic Activity ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Light Illumination ◽

X Ray ◽

Photo Catalytic Activity ◽

Visible Light Active ◽

Adsorption Desorption

The advantage of doping of TiO2 with copper has been utilized for enhanced degradation of pesticide under visible light irradiation. The sol–gel method has been undertaken for the synthesis of copper-doped TiO2 by varying the dopant loadings from 0.25 wt.% to 1.0 wt.% of Cu2+ . The doped samples were characterized by UV-Visible Diffuse Reflectance Spectroscopy (DRS), N2 adsorption–desorption (BET), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometry (EDS). The photocatalytic activity of the catalyst was tested by degradation of dichlorvos under visible light illumination. The results found that 0.75 wt.% of Cu2+ doped nanocatalysts have better photo catalytic activity than the rest of percentages doped, undoped TiO2 and Degussa P25. The reduction of band gap was estimated and the influence of the process parameters on photo catalytic activity of the catalyst has been explained.

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