Mesoporous TiO2 Implanted ZnO QDs for the Photodegradation of Tetracycline: Material Design, Structural Characterization and Photodegradation Mechanism

A sol-gel method was used to prepare a mesoporous TiO2 implanted with a ZnO quantum dot photocatalyst (TZQ) for the photodegradation of tetracycline (TC) under fluorescent light irradiation. Scanning electron microscopy (SEM) shows the presence of cavities on the photocatalyst surface due to the use of starch as a synthetic template, where the nitrogen sorption results indicate that TZQ contains mesopores with reduced size (ca. 4.3 nm) versus the pore size of the parent meso-TiO2 (ca. 7.5 nm). The addition of ZnO quantum dots (QDs) resulted in spherically-shaped binary composite particles in layers onto the surface of TiO2. The coexistence of the ZnO QDs and TiO2 phase was observed using high resolution-transmission electron microscopy (HR-TEM). The photodegradation of TC was carried out in a homemade reactor equipped with two fluorescent lights (24 W each) and within 90 min of irradiation, 94.6% of TC (40 mg L−1) was photodegraded using 250 mg L−1 of TZQ at pH 9. The major reactive oxygen species identified from the scavenging tests were O2●− followed by HO●. The deconvolution of the photoluminescence spectrum of TZQ indicates the presence of a strong quantum confinement effect (QCE) of the ZnO QDs, a defect related to Ti-species and oxygen. The analysis of the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS) suggest two photodegradation pathways. The pathways were validated using the Fukui function approach and the Wheland localisation approach. This simple and efficient photocatalytic technology is anticipated to benefit small-scale animal husbandries and aquaculture operators that have limited access to sustainable water treatment technology.

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The Effects of Zinc Oxide (ZnO) Quantum Dots (QDs) Embedment on the Physicochemical Properties and Photocatalytic Activity of Titanium Dioxide (TiO2) Nanoparticles

Journal of Physical Science ◽

10.21315/jps2021.32.2.6 ◽

2021 ◽

Vol 32 (2) ◽

pp. 71-85

Author(s):

Anwar Iqbal ◽

Usman Saidu ◽

Farook Adam ◽

Srimala Sreekantan ◽

Normawati Jasni ◽

...

Keyword(s):

Quantum Dots ◽

Zinc Oxide ◽

Titanium Dioxide ◽

Physicochemical Properties ◽

Quantum Confinement Effect ◽

Sol Gel ◽

Average Crystallite Size ◽

Fluorescent Light ◽

Zno Quantum Dots ◽

Zno Qds

In this study, a detailed investigation on the effect of zinc oxide (ZnO) quantum dots (QDs) embedment on the physicochemical properties of anatase titanium dioxide (TiO2) was conducted. The highly porous nanocomposite labelled as ZQT was prepared via the sol-gel assisted hydrothermal method. The powder X-ray diffraction (XRD) analysis indicates that the average crystallite size of the ZnO QDs, anatase TiO2 (TiO2 NPs) and ZQT were 4.45 nm, 9.22 nm and 11.38 nm, respectively. Photoluminescent (PL) analysis detected the presence of defects related to TiO2, oxygen vacancies and quantum confinement effect (QCE) of the ZnO QDs in ZQT. These features enhanced the photodegradation of tetracycline (TC) under 48 watt of fluorescent light irradiation when ZQT (98.0%) was used compared to TiO2NPs (32.4%) and ZnO QDs (68.8%). The photodegradation activity was driven by O2●− followed by ●OH and h+.

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Floating ZnO QDs-Modified TiO2/LLDPE Hybrid Polymer Film for the Effective Photodegradation of Tetracycline under Fluorescent Light Irradiation: Synthesis and Characterisation

Molecules ◽

10.3390/molecules26092509 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2509

Author(s):

Anwar Iqbal ◽

Usman Saidu ◽

Farook Adam ◽

Srimala Sreekantan ◽

Noorfatimah Yahaya ◽

...

Keyword(s):

Polymer Film ◽

Quantum Confinement Effect ◽

Photogenerated Electron ◽

Negative Energy ◽

Significant Loss ◽

Light Irradiation ◽

Fluorescent Light ◽

Hybrid Polymer ◽

Photocatalytic Ability ◽

Zno Qds

In this work, mesoporous TiO2-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO2. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O2●−. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).

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Blue Emitting BaAl2O4:Ce3+ Nanophosphors with High Color Purity and Brightness for White LEDs

Microscopy and Microanalysis ◽

10.1017/s1431927619014958 ◽

2019 ◽

Vol 25 (6) ◽

pp. 1466-1470 ◽

Cited By ~ 1

Author(s):

Rituparna Chatterjee ◽

Subhajit Saha ◽

Karamjyoti Panigrahi ◽

Uttam Kumar Ghorai ◽

Gopes Chandra Das ◽

...

Keyword(s):

Electron Microscopy ◽

Field Emission ◽

Sol Gel ◽

Blue Emission ◽

Diffraction Field ◽

White Leds ◽

Display Devices ◽

Transmission Electron ◽

Structure Morphology ◽

The Impact

AbstractIn this work, strongly blue emitting Ce3+-activated BaAl2O4 nanophosphors were successfully synthesized by a sol–gel technique. The crystal structure, morphology, and microstructure of the nanophosphors have been studied by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The photoluminescence spectra show the impact of concentration variation of Ce3+ on the photoluminescence emission of the phosphor. These nanophosphors display intense blue emission peaking at 422 nm generated by the Ce3+ 5d → 4f transition under 350 nm excitation. Our results reveal that this nanophosphor has the capability to take part in the emergent domain of solid-state lighting and field-emission display devices.

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Enhanced Photocatalytic Activity of CuWO4 Doped TiO2 Photocatalyst Towards Carbamazepine Removal under UV Irradiation

Separations ◽

10.3390/separations8030025 ◽

2021 ◽

Vol 8 (3) ◽

pp. 25

Author(s):

Chukwuka Bethel Anucha ◽

Ilknur Altin ◽

Emin Bacaksız ◽

Tayfur Kucukomeroglu ◽

Masho Hilawie Belay ◽

...

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Pure Tio2 ◽

Component Part ◽

Energy Yield ◽

Mechanical Agitation ◽

X Ray

Abatement of contaminants of emerging concerns (CECs) in water sources has been widely studied employing TiO2 based heterogeneous photocatalysis. However, low quantum energy yield among other limitations of titania has led to its modification with other semiconductor materials for improved photocatalytic activity. In this work, a 0.05 wt.% CuWO4 over TiO2 was prepared as a powder composite. Each component part synthesized via the sol-gel method for TiO2, and CuWO4 by co-precipitation assisted hydrothermal method from precursor salts, underwent gentle mechanical agitation. Homogenization of the nanopowder precursors was performed by zirconia ball milling for 2 h. The final material was obtained after annealing at 500 °C for 3.5 h. Structural and morphological characterization of the synthesized material has been achieved employing X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) N2 adsorption–desorption analysis, Scanning electron microscopy-coupled Energy dispersive X-ray spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) for optical characterization. The 0.05 wt.% CuWO4-TiO2 catalyst was investigated for its photocatalytic activity over carbamazepine (CBZ), achieving a degradation of almost 100% after 2 h irradiation. A comparison with pure TiO2 prepared under those same conditions was made. The effect of pH, chemical scavengers, H2O2 as well as contaminant ion effects (anions, cations), and humic acid (HA) was investigated, and their related influences on the photocatalyst efficiency towards CBZ degradation highlighted accordingly.

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Y3+ substituted Sr-hexaferrites: sol-gel synthesis, structural, magnetic and electrical characterization

Cerâmica ◽

10.1590/0366-69132019653742582 ◽

2019 ◽

Vol 65 (374) ◽

pp. 274-281 ◽

Cited By ~ 3

Author(s):

S. S. Satpute ◽

S. R. Wadgane ◽

S. R. Kadam ◽

D. R. Mane ◽

R. H. Kadam

Keyword(s):

Electron Microscopy ◽

Sol Gel ◽

Electrical Characterization ◽

Combustion Method ◽

Hexagonal Structure ◽

Strontium Hexaferrite ◽

X Ray Diffraction ◽

X Ray ◽

Morphological Studies ◽

Auto Combustion

Abstract Y3+ substituted strontium hexaferrites having chemical composition SrYxFe12-xO19 (x= 0.0, 0.5, 1.0, 1.5) were successfully synthesized by sol-gel auto-combustion method. The structural and morphological studies of prepared samples were investigated by using X-ray diffraction technique, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy. The X-ray diffraction pattern confirmed the single-phase hexagonal structure of yttrium substituted strontium ferrite and the lattice parameters a and c increased with the substitution of Y3+ ions. The crystallite size also varied with x content from 60 to 80 nm. The morphology was studied by FE-SEM, and the grain size of nanoparticles ranged from 44 to 130 nm. The magnetic properties were investigated by using vibrating sample magnetometer. The value of saturation magnetization decreased from 49.60 to 35.40 emu/g. The dielectric constant decreased non-linearly whereas the electrical dc resistivity increased with the yttrium concentration in strontium hexaferrite.

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Efficient Removal of Levofloxacin by Activated Persulfate with Magnetic CuFe2O4/MMT-k10 Nanocomposite: Characterization, Response Surface Methodology, and Degradation Mechanism

Water ◽

10.3390/w12123583 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3583

Author(s):

Junying Yang ◽

Minye Huang ◽

Shengsen Wang ◽

Xiaoyun Mao ◽

Yueming Hu ◽

...

Keyword(s):

Electron Microscopy ◽

Response Surface Methodology ◽

Response Surface ◽

Photoelectron Spectroscopy ◽

Degradation Mechanism ◽

Sol Gel ◽

Combustion Method ◽

Copper Ferrite ◽

X Ray ◽

Rsm Model

In this study, a magnetic copper ferrite/montmorillonite-k10 nanocomposite (CuFe2O4/MMT-k10) was successfully fabricated by a simple sol-gel combustion method and was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunner–Emmett–Teller (BET) method, vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS). For levofloxacin (LVF) degradation, CuFe2O4/MMT-k10 was utilized to activate persulfate (PS). Due to the relative high adsorption capacity of CuFe2O4/MMT-k10, the adsorption feature was considered an enhancement of LVF degradation. In addition, the response surface methodology (RSM) model was established with the parameters of pH, temperature, PS dosage, and CuFe2O4/MMT-k10 dosage as the independent variables to obtain the optimal response for LVF degradation. In cycle experiments, we identified the good stability and reusability of CuFe2O4/MMT-k10. We proposed a potential mechanism of CuFe2O4/MMT-k10 activating PS through free radical quenching tests and XPS analysis. These results reveal that CuFe2O4/MMT-k10 nanocomposite could activate the persulfate, which is an efficient technique for LVF degradation in water.

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Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽

10.3390/ma12020224 ◽

2019 ◽

Vol 12 (2) ◽

pp. 224 ◽

Cited By ~ 5

Author(s):

Jung-Eun Park ◽

Yong-Seok Jang ◽

Tae-Sung Bae ◽

Min-Ho Lee

Keyword(s):

Electron Microscopy ◽

Carbon Nanotubes ◽

Sol Gel ◽

Pure Titanium ◽

Cell Proliferation And Differentiation ◽

Transmission Electron ◽

Proliferation And Differentiation ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

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High-Resolution Electron Microscopy on Epitaxial Pb(Mg1/3Nb2/3)O3Film Prepared by Sol-Gel Method

Japanese Journal of Applied Physics ◽

10.1143/jjap.30.l1052 ◽

1991 ◽

Vol 30 (Part 2, No. 6A) ◽

pp. L1052-L1055 ◽

Cited By ~ 19

Author(s):

Kumi Okuwada ◽

Shin-ichi Nakamura ◽

Motomasa Imai ◽

Keiichi Kakuno

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Sol Gel ◽

High Resolution Electron Microscopy ◽

Gel Method ◽

Sol Gel Method ◽

Resolution Electron

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Nickel and sulfur codoped TiO2 nanoparticles for efficient visible light photocatalytic activity

Journal of Inorganic and Organometallic Polymers and Materials ◽

10.1007/s10904-021-01914-5 ◽

2021 ◽

Author(s):

Mehala Kunnamareddy ◽

Ranjith Rajendran ◽

Megala Sivagnanam ◽

Ramesh Rajendran ◽

Barathi Diravidamani

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Visible Light ◽

Light Absorption ◽

Fourier Transforms ◽

Phase Particle ◽

Energy Dispersive Spectrometer ◽

Sol Gel ◽

Bandgap Energy ◽

Visible Light Absorption

AbstractIn this work, Nickel (Ni) and sulfur (S) codoped TiO2 nanoparticles were prepared by a sol-gel technique. The as-prepared catalyst was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), FT-Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS) for investigating crystal structure, crystal phase, particle size and bandgap energy of these samples. The photocatalytic performances of all the prepared catalysts have been investigated for the degradation of methylene blue (MB) under visible light irradiation. It was noticed that Ni-S codoped TiO2(Ni-S/TiO2) nanoparticles exhibited much higher photocatalytic activity compared with pure, Ni and S doped TiO2 due to higher visible light absorption and probable decrease in the recombination of photo-generated charges. It was decided that the great visible light absorption was created for codoped TiO2 by the formation of impurity energy states near both the edges of the collection, which works as trapping sites for both the photogenerated charges to decrease the recombination process.

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