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

2013 ◽  
Vol 6 (2) ◽  
pp. 245-255 ◽  
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.

Synthesis of coral-globular-like composite Ag/TiO2-SnO2 and its photocatalytic degradation of rhodamine B under multiple modes

2017 ◽  
Vol 76 (8) ◽  
pp. 2120-2132 ◽  
Author(s):  
Q. Song ◽  
L. Li ◽  
N. Zhuo ◽  
H. N. Zhang ◽  
X. Chen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Organic Dyes ◽  
Uv Light ◽  
Sol Gel ◽  
X Ray ◽  
Tio2 Anatase

Taking cetyltrimethylammonium bromide (CTAB) as the template and using TiO2 as the substrate, coral-globular-like composite Ag/TiO2-SnO2 (CTAB) was successfully synthesized by the sol–gel combined with a temperature-programmed treatment method. X-ray diffraction, scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, SEM combined with X-ray energy dispersive spectroscopy, and N2 adsorption–desorption tests were employed to characterize samples' crystalline phase, chemical composition, morphology and surface physicochemical properties. Results showed that composites not only had TiO2 anatase structure, but also had some generated SnTiO4, and the silver species was metallic Ag0. Ag/TiO2-SnO2 (CTAB) possessed a coral-globular-like structure with nanosheets in large quantities. The photocatalytic activity of Ag/TiO2-SnO2 (CTAB) had studied by degrading organic dyes under multi-modes, mainly using rhodamine B as the model molecule. Results showed that the coral-globular-like Ag/TiO2-SnO2 (CTAB) was higher photocatalytic activity than that of commercial TiO2, Ag/TiO2-SnO2, TiO2-SnO2 (CTAB), and TiO2-SnO2 under ultraviolet light irradiation. Moreover, Ag/TiO2-SnO2 (CTAB) composite can significantly affect the photocatalytic degradation under multi-modes including UV light, visible light, simulated solar light and microwave-assisted irradiation. Meanwhile, the photocatalytic activity of Ag/TiO2-SnO2 (CTAB) was maintained even after three cycles, indicating that the catalyst had good usability.

Influence of Surfactant on the Phase Transformation of Bi2O3 and its Photocatalytic Activity

2019 ◽  
Vol 72 (4) ◽  
pp. 295 ◽  
Author(s):  
Kasinathan Karthik ◽  
K. R. Sunaja Devi ◽  
Dephan Pinheiro ◽  
Sankaran Sugunan
Keyword(s):  
Photocatalytic Activity ◽  
Bismuth Oxide ◽  
Rhodamine B ◽  
Environmental Remediation ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Lauryl Sulfate ◽  
Polyethylene Glycol 400 ◽  
Excellent Photocatalytic Activity ◽  
Bismuth Oxide Nanoparticles

Bismuth oxide with its unique narrow bandgap has gained significant attention in the field of photocatalysis. A new and efficient method to synthesise bismuth oxide with tuneable properties is proposed herein. A surfactant assisted modified sol–gel method is used to synthesise bismuth oxide with excellent photocatalytic activity for the degradation of Rhodamine B dye. Three different surfactants, namely polyethylene glycol-400, sodium lauryl sulfate, and cetyltrimethylammonium bromide (CTAB) have been used. The fabricated bismuth oxide nanoparticles were characterised by X-ray diffraction, IR, scanning electron microscopy, and UV-diffuse reflectance spectroscopy analysis. Evolution of both the α and β crystalline phases of bismuth oxide was observed. The bandgap of the synthesised bismuth oxides ranges from 2.03 to 2.37eV. The CTAB assisted synthesised bismuth oxide with a bandgap of 2.19eV showed the highest photocatalytic activity of 93.6% under visible light for the degradation of Rhodamine B. This bismuth oxide based catalyst opens a new avenue for efficient photocatalysis for environmental remediation.

Photocatalytic Activity of SiO2/TiO2 Supported on Glass Fiber under Vsible Light Irradiation

2011 ◽  
Vol 239-242 ◽  
pp. 571-574
Author(s):  
Xiang Chao Zhang ◽  
Yun Long Li ◽  
Zhong Xin Lin ◽  
Shi Ying Zhang
Keyword(s):  
Visible Light ◽  
Glass Fiber ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Glass Fibers ◽  
Sol Gel ◽  
Catalytic Efficiency ◽  
Atomic Ratio ◽  
Light Irradiation ◽  
Photocatalytic Decomposition

A SiO2/TiO2 supported on glass fibers photocatalyst with visible light activity were synthesized by sol-gel technology, butyl titanate as a Ti source, and tetraethylorthosilicate (TEOS) as a Si source. The photocatalytic activitie under visible light of SiO2/TiO2 supported on glass fibers were evaluated by the photocatalytic decomposition of methylene blue. The samples were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS). The results show that the optical absorption edges of the SiO2/TiO2 showed red shift with increasing the dopant of SiO2. The sample of SiO2/TiO2 supported on glass fiber (atomic ratio of Si/Ti=0.05) has the highest catalytic efficiency under visible light irradiation.

Mesostructured Anatase TiO2 for Visible Light and UV Photocatalysis With Confinement Effect and Semiconductor Coupling

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Florence Bosc ◽  
André Ayral ◽  
Nicolas Keller ◽  
Valérie Keller
Keyword(s):  
Visible Light ◽  
Partial Pressure ◽  
Active Sites ◽  
Reaction Rate ◽  
High Efficiency ◽  
Flow Reactor ◽  
Sol Gel ◽  
Confinement Effect ◽  
Tio2 Anatase ◽  
Photogenerated Charge Separation

Hexagonal and cubic mesostructured TiO2 anatase were synthesized by a templating sol-gel method using triblock copolymers as structuring agents, and used as photocatalysts for providing geometrical assistance to a photocatalytic reaction. The visible light and UV photocatalytic removal of gas-phase concentrated toluene (110ppm) within an annular flow-reactor was used as a tool to evidence the benefit to use mesostructured photocatalysts. The coupling of low amounts of WO3 with mesostructured anatase led to high efficiency using visible light and UV activation. The highly positive effect of WO3 on the toluene removal efficiency was attributed to the coupling between TiO2 and WO3 semiconductors, leading to an improved photogenerated charge separation and thus a weaker charge recombination. The hypothesis of a confinement effect of the reactants inside the mesostructured photocatalyst was put forward to explain the photocatalytic performances obtained under visible light and UV activation. This confinement effect would be based on the inner partial pressure concept. It consists of an increase in the partial pressure of the reactants next to the active sites inside the nanometric cavities of the ordered structure, while the apparent macroscopic partial pressures, outside the mesostructure, would remain unchanged. According to a traditional reaction rate law, such an increase results in the increase in the reaction rate. The photon-assisted reaction could be considered as “structure-assisted,” the geometrical assistance being provided by the surrounding ordered TiO2 walls of the mesostructure.

Enhancement of Adsorption-Photocatalysis of Malachite Green using Oil Palm Biomass Derived Activated Carbon/ Titanium Dioxide Composite

2020 ◽  
Vol 16 ◽  
Author(s):  
Yean Ling Pang ◽  
Wen Shun Teh ◽  
Steven Lim ◽  
Ahmad Zuhairi Abdullah ◽  
Hwai Chyuan Ong ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Activated Carbon ◽  
Malachite Green ◽  
Organic Dyes ◽  
Degradation Kinetics ◽  
Sol Gel ◽  
Weight Ratio ◽  
Oxygen Demand ◽  
Halogen Lamp ◽  
Tio2 Particles

Background: Nowadays, an effective wastewater treatment become a hot research topic in the field of environment. A series of novel activated carbon/ titanium dioxide (AC/TiO2) composites at various weight ratio, were synthesised using sol-gel method and were characterised using XRD, SEM-EDX, FT-IR, TGA and surface area analysis. Method: TiO2 particles were successfully incorporated on the AC surface and were mainly composed of Ti, O and C atoms. The AC/TiO2 composites were made up of spherical TiO2 particles agglomerated on the smooth tubular and porous structure of AC. The photocatalytic efficiency was influenced by the weight proportion of AC:TiO2 and the degradation process was attributed to the adsorption and photocatalytic processes. Results: It was found that 2.5 g/L AC/TiO2 at a weight ratio of 3:1 on an initial Malachite Green concentration of 10 mg/L at 50 °C led to a degradation efficiency of 96.3 % in 7.5 minutes under halogen lamp. A chemical oxygen demand (COD) removal of 96.7 % was also recorded. Reusability of AC/TiO2 composite and kinetic study of the photodegradation of Malachite Green were also investigated. The recycled AC/TiO2 composite achieved high catalytic performance (83.1 %) after one catalytic cycle. Conclusion: The degradation kinetics of Malachite Green at various solution temperatures were fitted to the pseudo first-order reactions and the activation energy for the degradation of Malachite Green was 21.48 kJ/mol. This work demonstrated that AC/TiO2 composite is a promising material for photocatalytic degradation of organic dyes.

scholarly journals Photocatalytic Degradation of Single and Binary Mixture of Brilliant Green and Rhodamine B Dyes by Zinc Sulfide Quantum Dots

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7686
Author(s):  
Peter A. Ajibade ◽  
Abimbola E. Oluwalana
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Brilliant Green ◽  
Organic Dyes ◽  
Degradation Efficiency ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
Tauc Plot ◽  
Diffraction Patterns

We present the preparation of octadecylamine-capped ZnS quantum dots from bis(morpholinyldithiocarbamato)Zn(II) complex. The complex was thermolyzed at 130 °C in octadecylamine at different times, to study the effect of reaction time on the morphological and photocatalytic properties of the ZnS quantum dots. Powder X-ray diffraction patterns confirmed a hexagonal wurtzite crystalline phase of ZnS, while HRTEM images showed particle sizes of about 1–3 nm, and energy band gaps of 3.68 eV (ZnS–1), 3.87 eV (ZnS–2), and 4.16 eV (ZnS–3) were obtained from the Tauc plot for the ZnS nanoparticles. The as-prepared ZnS were used as photocatalysts for the degradation of brilliant green, rhodamine B, and binary dye consisting of a mixture of brilliant green-rhodamine B. The highest photocatalytic degradation efficiency of 94% was obtained from ZnS–3 with low photoluminescence intensity. The effect of catalytic dosage and pH of the dyes solution on the photocatalytic process shows that pH 8 is optimal for the degradation of brilliant green, while pH 6.5 is the best for photocatalytic degradation of rhodamine B. The degradation of the binary dyes followed the same trends. The effect of catalytic dosage shows that 1 mg mL−1 of the ZnS nano-photocatalyst is the optimum dosage for the degradation of organic dyes. Reusability studies show that the ZnS quantum dots can be reused five times without a significant reduction in degradation efficiency.

scholarly journals Synthesis and Characterization of TiO2-ZnO-MgO Mixed Oxide and Their Antibacterial Activity

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 698 ◽  
Author(s):  
Luis Anaya-Esparza ◽  
Efigenia Montalvo-González ◽  
Napoleón González-Silva ◽  
María Méndez-Robles ◽  
Rafael Romero-Toledo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Mixed Oxide ◽  
Antimicrobial Agents ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Sol Gel ◽  
Industrial Applications ◽  
Pure Tio2 ◽  
Tio2 Anatase

TiO2-ZnO-MgO mixed oxide nanomaterials (MONs) were synthetized via the sol-gel method and characterized by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), nitrogen physisorption analysis, X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Fourier transform infrared spectroscopy (FTIR), and color (Luminosity (L), a, b, Chrome, hue) parameters. Furthermore, the antimicrobial activity of the MONs was tested against Escherichia coli (EC), Salmonella paratyphi (SP), Staphylococcus aureus (SA), and Listeria monocytogenes (LM). The MONs presented a semi globular-ovoid shape of ≤100 nm. Samples were classified as mesoporous materials and preserved in the TiO2 anatase phase, with slight changes in the color parameters of the MONs in comparison with pure TiO2. The MONs exhibited antimicrobial activity, and their effect on the tested bacteria was in the following order: EC > SP > SA > LM. Therefore, MONs could be used as antimicrobial agents for industrial applications.

Optimized photocatalytic degradation of caffeic acid by sol–gel TiO2

2015 ◽  
Vol 71 (6) ◽  
pp. 878-884 ◽  
Author(s):  
Xiomara L. García-Montelongo ◽  
Azael Martínez-de la Cruz ◽  
David Contreras ◽  
Héctor D. Mansilla
Keyword(s):  
Caffeic Acid ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Tio2 Anatase ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal Structure ◽  
Diffuse Reflectance Infrared ◽  
Adsorption Desorption

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%.

scholarly journals DEGRADASI SENYAWA RHODAMIN B SECARA SONOLISIS DENGAN PENAMBAHAN TiO2 HASIL SINTESA MELALUI PROSES SOL-GEL

2015 ◽  
Vol 1 (1) ◽  
pp. 64
Author(s):  
Syukri Arief ◽  
Safni ◽  
Putri Perdana Roza
Keyword(s):  
Rhodamine B ◽  
Sol Gel ◽  
Titanium Isopropoxide ◽  
Optimum Temperature ◽  
Tio2 Anatase ◽  
Sol Gel Process ◽  
Tio2 Rutile ◽  
Rhodamin B

 ABSTRACTDegradation of rhodamine B had been done by sonolysis method. Optimum temperature sonolysis were found of 41-50 oC. In this condition, rhodamine B 2 mg/L could be degradated around 64.04% during 6 hours sonolysis. Percentage degradation of rhodamine B enhanced by addition of TiO2 in solution. TiO2 was prepared with sol-gel process using titanium isopropoxide (TIP), isopropanol and dietanolamine (DEA) as precursor. It was heated on 500 oC and 700 oC in order to get TiO2-anatase dan TiO2-rutile. Rhodamine B 2 mg/L could be degradated around 68.48 and 90.00 % during 6 hours sonolysis on optimum temperature with addition of 0.1 g  TiO2-rutile and TiO2-anatase, respectively. Keyword: rhodamine B, sonolysis, sol-gel

Structural, Morphological and Optical Bandgap Analysis of Multifunction Applications of Y2O3 -ZnO Nanocomposites : Varistors and Visible Photocatalytic Degradations of Wastewater

2021 ◽  
Author(s):  
T.H AlAbdulaal ◽  
Manal AlShadidi ◽  
Mai Hussien ◽  
Ganesh Vanga ◽  
Abdel-Fatah Bouzidi ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Diffuse Reflectance Spectroscopy ◽  
Organic Dyes ◽  
Low Cost ◽  
Combustion Method ◽  
Ac Electrical Conductivity ◽  
Nanoparticle Structure ◽  
Yttrium Doping

Abstract In this study, a combustion method as an efficient, easy, low-cost, and eco-friendly technique was used to synthesize nano-ZnO as a matrix with different yttrium doping ratios with different doping concentrations. Not only X-ray diffraction (XRD), but also scanning electron microscopy (SEM), and Fourier transformation Infrared spectroscopy (FT-IR) technique employed to characterize the structural and surface morphology of the Y2O3-ZnO nanocomposites. The obtained results supported ZnO's growth from crystalline to satisfactory nanoparticle structure by changing the yttrium doping concentrations inside ZnO nanoparticles. Moreover, UV-Vis diffuse reflectance spectroscopy, AC electrical conductivity, and current-voltage characteristics were considered to characterize the effects of yttrium doping on the energy bandgaps and electrical/dielectric properties and discussed the parameters of the ceramic varistors of the studied Y2O3-ZnO nano-complex oxides. The photocatalytic degradation efficiency of phenol, Methylene Blue, and Rhodamine B was investigated using all prepared Y2O3-ZnO nanostructured samples. As the yttrium doping ratios increased, the photocatalytic efficiency increased. After the addition of moderate Y3+ ions-doping, Further generation of hydroxyl radicals over ZnO. For Y2O3-ZnO (S5), the optimal photocatalyst is a degradation of 100 % of phenol, Methylene Blue, and Rhodamine B solutions compared to 80% of photocatalysis for ZnO stand alone. The prepared Y2O3-ZnO nanostructured materials are considered novel potential candidates in broad nano-applications ranging from biomedical and photocatalytic degradation for organic dyes and phenol to environmental and varistor applications.

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