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

Molecules ◽  
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).

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

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+.

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

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1205
Author(s):  
Anwar Iqbal ◽  
Usman Saidu ◽  
Srimala Sreekantan ◽  
Mohammad Norazmi Ahmad ◽  
Marzaini Rashid ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Confinement Effect ◽  
Sol Gel ◽  
Material Design ◽  
Mesoporous Tio2 ◽  
Small Scale ◽  
Fluorescent Light ◽  
Treatment Technology ◽  
Flight Mass Spectrometry ◽  
Zno Qds

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.

scholarly journals ZnO Surface Doping to Enhance the Photocatalytic Activity of Lithium Titanate/TiO2 for Methylene Blue Photodegradation under Visible Light Irradiation

Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 301-318 ◽  
Author(s):  
Anwar Iqbal ◽  
N. H. Ibrahim ◽  
Nur Ruzaina Abdul Rahman ◽  
K. A. Saharudin ◽  
Farook Adam ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Surface Defects ◽  
Lithium Titanate ◽  
Significant Loss ◽  
Light Irradiation ◽  
Photocatalytic Ability ◽  
Transmission Electron

Wastewater contaminated with dyes produced by textile industries is a major problem due to inadequate treatment prior to release into the environment. In this paper, the ability of ZnO to enhance the interfacial photocatalytic activity of lithium titanate/TiO2 (LTO/TiO2) for the photodegradation of methylene blue (MB) under visible light irradiation (4.38 mW/cm2) was assessed. The ZnO-doped lithium titanate/TiO2 (ZnO/LTO/TiO2) was synthesized using a combination of hydrothermal and wetness impregnation methods. The high-resolution transmission electron microscope (HRTEM) and X-ray Diffraction (XRD) analyses indicate that the ZnO/LTO/TiO2 contain several phases (ZnO, LTO, and TiO2). The adsorption capacity of LTO/TiO2 (70%) was determined to be higher compared to its photocatalytic activity (25%), which is attributed to the strong interaction between the Li and surface oxygen atoms with the MB dye molecules. The introduction of ZnO improved the photocatalytic ability of LTO/TiO2 by 45% and extended the life span of ZnO/LTO/TiO2. The ZnO/LTO/TiO2 can be reused without a significant loss up to four cycles, whereas LTO/TiO2 had reduced adsorption after the second cycle by 30%. The ZnO increased the surface defects and restrained the photo-induced electrons (e−) from recombining with the photo-induced holes (h+). Scavenging tests indicated that the hydroxyl radicals played a major role in the photodegradation of MB, which is followed by electrons and holes.

One-Step Hydrothermal Synthesis of Bi2S3-TiO2-RGO Composites with Enhanced Visible Light Photocatalytic Activities

NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850051 ◽  
Author(s):  
Yanan Li ◽  
Zhongmin Liu ◽  
Yaru Li ◽  
Yongchuan Wu ◽  
Jitao Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Photogenerated Electron ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Photocatalytic Ability ◽  
Transmission Electron ◽  
Light Region ◽  
Infrared Spectrometer ◽  
One Step

The Bi2S3-TiO2-RGO composites were synthesized by a facile one-step hydrothermal method and applied for the photocatalytic degradation of Rhodamine B (Rh B) under the visible light. The Bi2S3-TiO2-RGO composites were characterized by transmission electron microscopy, X-ray diffraction, Raman and Fourier transform infrared spectrometer. The results indicated that the Bi2S3-TiO2-RGO composites were successfully prepared, and Ti-O-C and S-C bonds were existing among Bi2S3, TiO2 as well as RGO. Furthermore, the photocatalytic ability of Bi2S3-TiO2-RGO composites was excellent under visible light due to its responding to the whole visible light region, low recombination rate of photogenerated electron–hole pairs and relatively negative conduction band. Rh B photocatalytic degradation rate was 99.5% after 50[Formula: see text]min and still could reach 98.4% after five cycles. Finally, a formation mechanism as well as a photocatalytic mechanism of Bi2S3-TiO2-RGO composites were proposed based on the experimental results.

Nonmetal–metal–semiconductor-promoted P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst with superior photocatalytic activity and stability

2015 ◽  
Vol 3 (34) ◽  
pp. 17858-17865 ◽  
Author(s):  
Xiaohong Hu ◽  
Qi Zhu ◽  
Xinlong Wang ◽  
Naoki Kawazoe ◽  
Yingnan Yang
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Light Irradiation ◽  
Solar Light ◽  
Tio2 Photocatalyst ◽  
Photocatalytic Ability ◽  
Composite Photocatalyst ◽  
Gel Method ◽  
Simulated Solar Light ◽  
Solar Light Irradiation

P/Ag/Ag2O/Ag3PO4/TiO2 composite photocatalyst has been successfully prepared by a sol–gel method. It shows highly enhanced photocatalytic ability and stability under simulated solar light irradiation.

scholarly journals Magnetically separable AgI–BiOI/CoFe2O4 hybrid composites for Hg0 removal: characterization, activity and mechanism

RSC Advances ◽  
2017 ◽  
Vol 7 (50) ◽  
pp. 31448-31456 ◽  
Author(s):  
Lixiang Zhang ◽  
Anchao Zhang ◽  
Hao Lu ◽  
Zhijun Sun ◽  
Wei Sheng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Hybrid Composites ◽  
Light Irradiation ◽  
Fluorescent Light ◽  
Magnetically Separable

AgI0.3BiOI/CoFe2O4, a magnetically separable photocatalyst, exhibited a superior photocatalytic activity of Hg0 removal under fluorescent light irradiation.

Enhanced photocatalytic activity of a pine-branch-like ternary CuO/CuS/ZnO heterostructure under visible light irradiation

2019 ◽  
Vol 43 (28) ◽  
pp. 11342-11347 ◽  
Author(s):  
Fa Cao ◽  
Zhihu Pan ◽  
Xiaohong Ji
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Organic Dyes ◽  
Light Irradiation ◽  
Photocatalytic Ability ◽  
Visible Light Photocatalytic

A pine-branch-like ternary CuO/CuS/ZnO heterostructure exhibits enhanced visible light photocatalytic ability toward organic dyes.

Plasmon-Induced Photodegradation of Toxic Pollutants with Ag/AgI/Bi2WO6 under Visible-Light Irradiation

2013 ◽  
Vol 807-809 ◽  
pp. 1534-1542 ◽  
Author(s):  
Ming Sheng Gui ◽  
Peng Fei Wang ◽  
Miao Miao Tang ◽  
Dong Yuan
Keyword(s):  
Surface Plasmon Resonance ◽  
Visible Light ◽  
Surface Plasmon ◽  
Visible Light Irradiation ◽  
Plasmon Resonance ◽  
Photogenerated Electron ◽  
Light Irradiation ◽  
Ag Nps ◽  
Electron Hole ◽  
Band Position

The Ag/AgI/Bi2WO6photocatalysts were successfully synthesized by deposition-precipitation and photoreduction methods. The catalyst showed high and stable photocatalytic activity for the degradation of the RhB under visible light irradiation (λ>400 nm). On the basis of a new plasmonic photocatalytic mechanism, the photogenerated electron-hole pairs are formed in Ag nanoparticles (NPs) due to surface plasmon resonance under visible-light irradiation. Then, the photoexcited electrons at the Ag NPs are injected into AgI. On the other hand, the band position shows that AgI and Bi2WO6have the matching band potentials in the AgI/Bi2WO6heterostructure composites. So the photoexcited electrons is ultimately transfer to the Bi2WO6conduction band (CB), photo-induced holes (hVB+) is transfer to the AgI valence band (VB) and the simultaneous transfer to compensative electrons from I-to the Ag NPS. This the result indicates that the high photosensitivity of noble metal Ag NPs due to surface plasmon resonance, which is not only improve the photocatalytic performance, but also offer a new idea for preparation of new photocatalysts .

scholarly journals Recent Advances in Doped Bi2O3 and its Photocatalytic Activity: A Review

2022 ◽  
Vol 9 (1) ◽  
pp. 216-230
Author(s):  
Bella Aprimanti Utami ◽  
Heri Sutanto ◽  
Eko Hidayanto
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Energy Gap ◽  
Light Irradiation ◽  
High Electron ◽  
Photocatalytic Ability ◽  
As Doping ◽  
Electron Hole Pair ◽  
Defect Recognition

Bismuth Oxide (Bi2O3) has a very promising photocatalytic ability to degrade waste pollutants under visible light irradiation because it has a small energy gap of around 2.85-2.58 eV. Although it has excellent potential as a photocatalyst, Bi2O3 has the disadvantage of a high electron-hole pair recombination rate, which will reduce its photocatalytic activity. To overcome these problems, surface modifications, defect recognition, or doping of Bi2O3 are carried out to obtain a more effective and efficient photocatalyst to degrade waste pollutants under visible light irradiation. Several studies by researchers have been described for the modification of Bi2O3 by doping. Various types of doping are given, such as doping in elements or doping in the form of compounds to form composites. Based on several studies that have been described, appropriate doping has been shown to increase the photocatalytic activity of Bi2O3. Keywords: Bi2O3, Photocatalyst, Doping

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