The role of oxygen vacancy over ZnCr-layered double oxide in enhancing solar light-driven photocatalytic degradation of bisphenol A

2018 ◽  
Vol 15 (4) ◽  
pp. 226 ◽  
Author(s):  
Meiqing Chen ◽  
Pingxiao Wu ◽  
Qianqian Wei ◽  
Yajie Zhu ◽  
Shanshan Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Bisphenol A ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Organic Pollutants ◽  
Oxygen Vacancies ◽  
Solar Light ◽  
X Ray ◽  
Vis Spectroscopy

Environmental contextAn important goal in attempts to degrade environmental organic pollutants is the development of a photocatalyst that is responsive to visible light. We report a facile method for preparing a zinc-based photocatalyst with oxygen vacancies that efficiently degrades bisphenol A under solar light irradiation. The study will stimulate further investigations into the efficacy of other metal oxide nanostructures for the photocatalytic degradation of organic pollutants. AbstractTwo ZnCr-layered double oxides (ZnCr-LDO) were fabricated via different thermal treatment of the ZnCr-layered double hydroxide (ZnCr-LDH) precursor. ZnCr-V-700 and ZnCr-A-700 were obtained at 700 °C under vacuum and air, respectively. As X-ray diffraction revealed, both ZnCr-V-700 and ZnCr-A-700 were made up of ZnO and ZnCr2O4 spinel, and ZnCr-V-700 displayed a lower crystallinity and many uniform particles with oxygen vacancies. Scanning electron microscopy and transmission electron microscopy revealed that the particle size of ZnCr-V-700 was ~30 nm and its disordered crystallinity suggested the existence of oxygen vacancies. Notably, the ZnCr-LDO materials showed remarkably enhanced photocatalytic activity compared to the ZnCr-LDH precursor. ZnCr-V-700 was the most active material and more than 90 % of BPA was degraded after irradiation for 200 min with high mineralisation (up to 37 %). The results of Brunauer–Emmett–Teller surface area analysis, X-ray photoelectron spectroscopy, Raman and UV-vis spectroscopy and electron paramagnetic resonance spectroscopy showed that oxygen vacancies incorporated into ZnCr-V-700 played a key role in improving the photocatalytic performance by enhancing interfacial charge transfer and restricting the charge recombination. In addition, the uniform particle size, larger surface area and the coexistence of ZnO and ZnCr2O4 also played a synergistic role. In conclusion, this work not only provides a facile and low-cost method to prepare photocatalysts for treatment of wastewater containing BPA, but also supplies a new idea for improving the performance of photocatalysts.

Enhanced ofloxacin degradation efficiency on porous CeTi2O6 photocatalyst-CTAB induced porosity

2020 ◽  
Vol 16 ◽  
Author(s):  
Lili Yang ◽  
Chuanguo Li ◽  
Wenjie Zhang
Keyword(s):  
Electron Microscopy ◽  
Porous Structure ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Organic Pollutants ◽  
Photoelectron Spectroscopy ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Light Illumination ◽  
X Ray

BACKGROUND: Photocatalytic oxidation of organic pollutants in the environment has been studied for more than half a century. Titanate has the activity on degradation of organic pollutants under UV light illumination. Template directed sol-gel method is capable of producing porous structure in titanate during high temperature thermal treatment. METHODS: The materials were characterized using X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, surface area and pore size analyses, UV-Visible spectrometry, and X-ray photoelectron spectroscopy. Photocatalytic activity of the CeTi2O6 material was evaluated through ofloxacin degradation. RESULTS: Brannerite structured CeTi2O6 was the major component in the samples, and the addition of CTAB caused a slight growth of CeTi2O6 crystals. Porous structure formed in the porous sample after the removal of CTAB template, and the surface area and pore volume were greatly enlarged. The first order reaction rate constant for photocatalytic degradation of ofloxacin was 9.60×10-3 min-1 on the nonporous CeTi2O6 sample, and it was as large as 2.44×10-2 min-1 on the porous CeTi2O6 sample. The addition of CTAB can influence the physico-chemical properties of the porous CeTi2O6, such as the improved activity on photocatalytic degradation of ofloxacin. CONCLUSION: The CeTi2O6 samples were composed of majority brannerite CeTi2O6, and CeTi2O6 crystallite sizes for the nonporous and porous samples were 38.1 and 43.2 nm. The burning up of CTAB during calcination produced abundant pores in the porous material. After 50 min of reaction, photocatalytic degradation efficiencies on the nonporous and porous CeTi2O6 samples were 38.1% and 70.5%.

Preparation of Carbon-Encapsulated Fe Core-Shell Nanostructures by Confined Arc Plasma

2011 ◽  
Vol 688 ◽  
pp. 245-249 ◽  
Author(s):  
Zhi Qiang Wei ◽  
Xiao Yun Wang ◽  
Hua Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Core Shell ◽  
Arc Plasma ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

Special carbon encapsulated Fe core-shell nanoparticles with a size range of 15–40 nm were successfully prepared via confined arc plasma method. The composition, morphology, microstructure, specific surface area, particle size of the product by this process were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS) and BET N2adsorption. The experiment results shown that the carbon encapsulated Fe nanoparticles with clear core-shell structure, the core of the particles is body centered cubic (BCC) structure Fe, and the shell of the particles is disorder carbons. The particle size of the nanocapsules ranges from 15 to 40nm，with an averaged value about 30nm, the particles diameter of the core is about 16nm and the thickness of the shells is about 6-8 nm, and the specific surface area is 24 m2/g.

scholarly journals Photocatalytic Degradation of Organic Pollutant using Reduced Graphene Oxide

2019 ◽  
Vol 8 (4S2) ◽  
pp. 870-872
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Photocatalytic Degradation ◽  
Reduced Graphene Oxide ◽  
Organic Pollutant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Scaning Electron Microscopy

A simple eco friendly preparation of reduced graphene oxide from graphene oxide using strawberry extract is reported. As prepared reduced graphene oxide were characterized by X-Ray Diffraction, UV-Vis spectroscopy, Scaning electron microscopy and degradation performane of MB. The reduced graphene oxide was effectively degradation of MB.

Photocatalytic removal of 2-nitrophenol using silver and sulfur co-doped TiO2 under natural solar light

2015 ◽  
Vol 72 (3) ◽  
pp. 339-346 ◽  
Author(s):  
Mehrzad Feilizadeh ◽  
Amin Delparish ◽  
S. Toufigh Bararpour ◽  
Hamed Abedini Najafabadi ◽  
S. Mohammad Esmaeil Zakeri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Solar Light ◽  
Morphological Properties ◽  
Doped Tio2 ◽  
X Ray ◽  
Bare Tio2 ◽  
Co Doping ◽  
Co Doped

To overcome the drawback of poor solar light utilization brought about by the narrow photoresponse range of TiO2, a silver and sulfur co-doped TiO2 was synthesized. Using the prepared catalyst, solar photocatalytic degradation of 2-nitrophenol (2-NP) by a TiO2-based catalyst was studied for the first time. Effects of the co-doping on the structural, optical and morphological properties of the synthesized nanoparticles were investigated by different characterization methods: X-ray diffraction, N2 adsorption–desorption measurements, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, UV–visible diffuse reflectance spectroscopy and Fourier transform infrared spectroscopy. Solar experiments showed that the co-doping with silver and sulfur significantly increased the photocatalytic activity. In various initial concentrations of 2-NP more than 99% of the contaminant was decomposed by Ag-S/TiO2 in less than 150 minutes, while the degradation efficiency was much less in the presence of bare TiO2. Kinetic studies suggested that solar photocatalytic degradation of 2-NP is consistent with the Langmuir–Hinshelwood model. The rate constant of the reaction and adsorption constant of the modified photocatalyst were found to be 2.4 and 4.1 times larger than that of bare TiO2, respectively.

The Preparation of Bi-Pb-Sr-Ca-Cu-O Superconducting Powder for Thick Film Pastes

1989 ◽  
Vol 169 ◽  
Author(s):  
J. Hagberg ◽  
A. Uusimäki ◽  
J. Levoska ◽  
S Leppävuori ◽  
R Rautioaho
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Surface Area ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Oxalate Route

AbstractThe oxalate route was used to prepare (Bi-Pb) -Sr-Ca-Cu-O powder with the nominal composition Bi1.75Pb0.4Sr1.3Ca2.1Cu3.2Oy. This powder was decomposed/annealed at different temperatures between 434 and 795°C. They were investigated by thermogravimetric analysis, X-ray diffraction and transmission electron microscopy. Particle size distribution and surface area were also determined. The specific surface area decreased from a value of 16.5 m2/g for powder decomposed at 434 °C to 1.0 m2/g for powder decomposed at 795 °C. The measured mean particle size reached a minimum of 0.52 juri for powder decomposed at 589 °C.

scholarly journals Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Pore Diameter ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Photocatalytic Efficiency ◽  
Average Pore ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

scholarly journals Synthesis and characterization of Fe, Co, and Ni colloids in 2-mercaptoethanol

2020 ◽  
Vol 10 ◽  
pp. 184798042096688
Author(s):  
Galo Cárdenas-Triviño ◽  
Sergio Triviño-Matus
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Colloidal Dispersions ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Chemical Liquid Deposition ◽  
Liquid Deposition

Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.

scholarly journals Magnetically Recyclable Wool Keratin Modified Magnetite Powders for Efficient Removal of Cu2+ Ions from Aqueous Solutions

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1068
Author(s):  
Xinyue Zhang ◽  
Yani Guo ◽  
Wenjun Li ◽  
Jinyuan Zhang ◽  
Hailiang Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Ion Concentration ◽  
Bet Surface Area ◽  
Chemical Compositions ◽  
Ion Adsorption ◽  
X Ray ◽  
Wool Keratin

The treatment of wastewater containing heavy metals and the utilization of wool waste are very important for the sustainable development of textile mills. In this study, the wool keratin modified magnetite (Fe3O4) powders were fabricated by using wool waste via a co-precipitation technique for removal of Cu2+ ions from aqueous solutions. The morphology, chemical compositions, crystal structure, microstructure, magnetism properties, organic content, and specific surface area of as-fabricated powders were systematically characterized by various techniques including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), thermogravimetric (TG) analysis, and Brunauer–Emmett–Teller (BET) surface area analyzer. The effects of experimental parameters such as the volume of wool keratin hydrolysate, the dosage of powder, the initial Cu2+ ion concentration, and the pH value of solution on the adsorption capacity of Cu2+ ions by the powders were examined. The experimental results indicated that the Cu2+ ion adsorption performance of the wool keratin modified Fe3O4 powders exhibited much better than that of the chitosan modified ones with a maximum Cu2+ adsorption capacity of 27.4 mg/g under favorable conditions (0.05 g powders; 50 mL of 40 mg/L CuSO4; pH 5; temperature 293 K). The high adsorption capacity towards Cu2+ ions on the wool keratin modified Fe3O4 powders was primarily because of the strong surface complexation of –COOH and –NH2 functional groups of wool keratins with Cu2+ ions. The Cu2+ ion adsorption process on the wool keratin modified Fe3O4 powders followed the Temkin adsorption isotherm model and the intraparticle diffusion and pseudo-second-order adsorption kinetic models. After Cu2+ ion removal, the wool keratin modified Fe3O4 powders were easily separated using a magnet from aqueous solution and efficiently regenerated using 0.5 M ethylene diamine tetraacetic acid (EDTA)-H2SO4 eluting. The wool keratin modified Fe3O4 powders possessed good regenerative performance after five cycles. This study provided a feasible way to utilize waste wool textiles for preparing magnetic biomass-based adsorbents for the removal of heavy metal ions from aqueous solutions.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

Effect of Seedings on the Microstructure of Hydrated Alumina

2012 ◽  
Vol 554-556 ◽  
pp. 709-713
Author(s):  
Yan Hong Liu ◽  
Hong Wen Ma ◽  
Mei Tang Liu
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Decisive Role ◽  
Mechanism Study ◽  
Hydrated Alumina ◽  
Crystal Nucleus ◽  
X Ray ◽  
Intrinsic Mechanism ◽  
Scanning Electron

The morphology and particle size of boehmite play a decisive role on the application of alumina that derived from it. In this paper, we employed pseudoboehmite that produced from Al2 (SO4)3•18H2O and NH3•H2O at 70 °C, pH 7.5 as precursor to synthesize boehmite, and utilized different seeding when preparing pseudoboehmite and boehmite. To identify the influence of seeding on the microstructure of pseudoboehmite and boehmite, the products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and BET. The results indicate that the pseudoboehmite seeding has a significant influence on the morphology and particle size of pseudoboehmite to which we should pay high attention. However, the boehmite seeding does not play the role of crystal nucleus as expected. The further intrinsic mechanism study is ongoing.

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