scholarly journals W-Doped ZnO Photocatalyst for the Degradation of Glyphosate in Aqueous Solution

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 234
Author(s):  
Mariaconcetta Russo ◽  
Giuseppina Iervolino ◽  
Vincenzo Vaiano

In this paper, the photocatalytic degradation of glyphosate by zinc oxide (ZnO) photocatalysts doped with tungsten (W) was investigated under solar simulated light. The photocatalysts were successfully synthesized through a simple precipitation method and subsequently characterized by different techniques: Raman spectroscopy, UV–Vis, N2 adsorption at −196 °C, X-ray diffraction, and SEM analysis. In particular, all the prepared catalysts were characterized by a crystallite size of about 28 nm and a hexagonal wurtzite structure. After the W doping, the bandgap energy decreased from 3.22 of pure ZnO to 3.19 for doped ZnO. This allowed us to obtain good results in terms of glyphosate degradation and simultaneous mineralization under solar simulated lamps, making the process environmentally friendly and with almost zero energy costs. In particular, the best photocatalytic performance was obtained with 100 W-ZnO (prepared with 1.5 mol% of W). With this catalyst, after 180 min of exposure to solar simulated light, the glyphosate degradation and mineralization was equal to 74% and 30%, respectively. Furthermore, it has been shown that the best catalyst dosage was equal to 1.5 g/L. The study on the influence of pH evidenced that the best photocatalytic performances are obtained at spontaneous (neutral) pH conditions. Finally, to determine the main reactive species in the glyphosate oxidation, the effects of different radical scavengers were tested. The results evidenced that the glyphosate oxidation mechanism seems to be related mainly to the O2•− generated under simulated solar light irradiation, but also in minor part to h+.

2010 ◽  
Vol 143-144 ◽  
pp. 271-276
Author(s):  
Yan Qiang Jia ◽  
Dong Mei Shi ◽  
Jun Yan

Al-doped ZnO (AZO) nanoparticles were synthesized by using homogeneous precipitation method from Zn(AC)2•2H2O and Al(NO3)3•9H2O. X-ray diffraction (XRD) showed that the AZO nanoparticles were well assigned to hexagonal wurtzite structure, and that the Al3+ did enter the ZnO crystal lattice to substitute the position of Zn2+. Results from scanning electron microscope (SEM) showed that with increasing Al content, the the size of ZAO particles decreased. When Al content was 5 mol%, gives a more homogeneous and finer microstructure. At last, study the electromagnetic performance of AZO particles with different doping concentration of Al3+.


2020 ◽  
Vol 10 (7) ◽  
pp. 659
Author(s):  
Wondimagegn Kumala

The binary systems of ZnO-Fe<sub>2</sub>O<sub>3</sub> nanocomposites were synthesized by a precipitation method with aqueous solutions of Fe and Zn nitrate, whereas nitrogen-doped ZnO-Fe<sub>2</sub>O<sub>3</sub>, silver-doped ZnO-Fe<sub>2</sub>O<sub>3,</sub> and silver-nitrogen co-doped ZnO-Fe<sub>2</sub>O<sub>3</sub> nanocomposite were prepared by solid-state reaction. The structure and bandgap of the composites were studied using X-ray diffraction (XRD) and UV-visible diffuse reflectance spectroscopy (UV–vis). An aqueous model pollutant Methylene blue (MB) dye solution was used to evaluate photocatalytic degradation activities of the nanocomposites under visible light irradiation. Doping photocatalyst significantly increased the effectiveness of the photocatalyst in reducing bandgap energy. So 2.05 eV is the lowest energy, which is for Ag/N co-doped ZnO-Fe<sub>2</sub>O<sub>3 </sub>photocatalysts. Results of the experiment that involved the photocatalysts revealed that Methylene blue degradations of 45.11%, 47%, 51%, and 64.5% in 180 min under light radiation using ZnO-Fe<sub>2</sub>O<sub>3</sub>, Ag-doped ZnO-Fe<sub>2</sub>O<sub>3</sub>, N-doped ZnO-Fe<sub>2</sub>O<sub>3,</sub> and Ag/N co-doped ZnO-Fe<sub>2</sub>O<sub>3</sub>, respectively. The doped photocatalysts were all superior to the undoped ZnO-Fe<sub>2</sub>O<sub>3</sub>. The efficiency of Ag/N co-doped ZnO-Fe<sub>2</sub>O<sub>3 </sub>photocatalysts was higher on the photodegradation of MB at optimum PH, the load of Methylene blue photocatalyst which is 78%.


Cerâmica ◽  
2015 ◽  
Vol 61 (360) ◽  
pp. 457-461 ◽  
Author(s):  
V. D. Mote ◽  
Y. Purushotham ◽  
R. S. Shinde ◽  
S. D. Salunke ◽  
B. N. Dole

Abstract Yttrium-doped ZnO nanoparticles were synthesized by co-precipitation method to investigate structural, optical and antibacterial properties. X-ray diffraction analysis confirms hexagonal (wurtzite) structure with average crystallite size between 16 and 30 nm. Optical energy band gap decreaseswith increasing Y-doping concentration. ZnO nanoparticles were found to be highly effective against S. aureus and Y-doped ZnO nanoparticles against E. coli, B. subtilis and S. typhi. Undoped and Y-doped ZnO nanoparticles are good inorganic antimicrobial agents and can be synthesized by cost effective co-precipitation method.


2016 ◽  
Vol 12 (12) ◽  
pp. 4593-4600
Author(s):  
A. Srithar ◽  
J.C. Kannan ◽  
T.S. Senthil

In the present investigation, MnxZn1-xO (x = 0.05, 0.075 and 0.1%) nanoparticles have been synthesized by simple precipitation method. Their structural, morphological and optical properties were examined by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX), High resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Differential scanning calorimetry (DSC) and UV-Visible spectroscopy. The Powder X-ray diffraction studies confirmed that the manganese doped ZnO have a single phase nature with hexagonal wurtzite structure and Mn successfully incorporated into the lattice position of Zn in ZnO lattice. The FESEM and HRTEM images are coincided with each other for aggregation of particles in nature. The elemental analysis of doped samples has been evaluated by EDX. The antibacterial activity of Mn doped ZnO nanoparticles has also been examined.


2015 ◽  
Vol 827 ◽  
pp. 19-24 ◽  
Author(s):  
Nur Afifah ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh

In this study, the photocatalytic activity of pure Fe- doped ZnO and Fe- doped ZnO/Montmorillonite nanocomposite has been investigated for the degradation of malachite green under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier-transform infrared absorption, and electron spin resonance. The results showed that the photocatalytic efficiency is better in the presence of montmorillonite compared to pure Fe- doped ZnO. To detect the possible reactive species involved in degradation of organic dyes control experiments with introducing scavengers into the solution of organic dyes were carried out. It is found that electron plays an important role in the degradation of malachite green.


2019 ◽  
Vol 97 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Ye Zhao ◽  
Fan Tong ◽  
Mao Hua Wang

Pure and cobalt-doped ZnO nanoparticles (2.5, 5, 7.5, and 10 atom % Co) are synthesized by sol–gel method. The as-synthesized nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM) analysis. The nanoparticles of 0, 2.5, and 5 atom % Co-doped ZnO exhibited hexagonal wurtzite structure and have no other phases. Moreover, the (101) diffraction peaks position of Co-doped ZnO shift toward a smaller value of diffraction angle compared with pure ZnO powders. The results confirm that Co ions were well incorporated into ZnO crystal lattice. Simultaneously, Co doping also inhibited the growth of particles, and the crystallite size decreased from 43.11 nm to 36.63 nm with the increase in doping concentration from 0 to 10 atom %. The values of the optical band gap of all Co-doped ZnO nanoparticles gradually decreased from 3.09 eV to 2.66 eV with increasing Co content. Particular, the dielectric constant of all Co-doped ZnO ceramics gradually increased from 1.62 × 103 to 20.52 × 103, and the dielectric loss decreased from 2.36 to 1.28 when Co content increased from 0 to 10 atom %.


Author(s):  
Selma M.H. AL-Jawad ◽  
Zahraa S. Shakir ◽  
Duha S. Ahmed

ZnO/MWCNTs hybrid and doped with different concentration of Nickel element prepared by using Sol-gel been technique reported. All samples were prepared and characterized by X-Ray Diffraction Analysis (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM), and UV-Vis spectroscopy have been identified the structural, optical and morphological properties. X-ray diffraction showed the polycrystalline nature with hexagonal wutzite structure of hybrid and doped with Nickel. The crystalline size of the hybrid nanostructure was increasing from 23.73 nm to 34.59 nm. Besides, the UV-Vis spectroscopy showed a significant decrease in the band gap values from 2.97 eV to 2.01 eV. Whereas the FE-SEM analysis confirm the formation spherical shapes of ZnO NPs deposited on cylindrical tubes representing the MWCNTs. The antibacterial activity reveals that the inhibition zone of Ni doped-ZnO/MWCNTs hybrid was 28.5 mm, 26.5 mm toward E. coli and S. aureus bacteria, respectively.


2019 ◽  
Vol 969 ◽  
pp. 169-174
Author(s):  
R. Sivanand ◽  
S. Chellammal ◽  
S. Manivannan

In this paper, the effect of size variation of cadmium sulphide nanocrystallites which have been prepared by precipitation method is analyzed. These prepared samples were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive analysis of spectroscopy (EDAX) techniques. SEM analysis represents the morphological nature of prepared samples and EDAX indicates the confirmation of elements present in the sample. XRD analysis determines the size of the samples and identifies the structure using miller indices (h k l values) of the nanocrystallies matches with JCPDS. From the XRD analysis, the size variation which depends on dopant, capping agent are discussed and corresponding results are reported in this paper.


2020 ◽  
Vol 1007 ◽  
pp. 148-153
Author(s):  
Pimpaka Putthithanas ◽  
Supan Yodyingyong ◽  
Jeerapond Leelawattanachai ◽  
Wannapong Triampo ◽  
Noppakun Sanpo ◽  
...  

In this work, aluminum-doped ZnO (AZO) is synthesized for heat-shielding applications. A family of ethanolamine (EA: monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine TEA)) is used to control the morphology of aluminum-doped ZnO (AZO) synthesized via a simple solvothermal method at the temperature of 120°C for 6 h. The samples were characterized by field-emission scanning electron microscopy (FE-SEM). The formation of primary ZnO nanoparticles (NPs) showed that TEA yielded highly packed-spherical aggregates not found when DEA and MEA were used. X-ray diffraction (XRD) found that all AZO samples have peaks of the ZnO hexagonal wurtzite structure. XRD patterns of aluminum were found for >10 mol%. UV-Vis-NIR spectrophotometer was used to study the optical property and heat-shielding of the near-infrared region (NIR, the wavelength from 700 - 2500 nm). All AZO NPs of 0, 2, 4, and 10 mol% exhibited strong NIR shielding ability up to 80% insulation. From these results, the AZO NPs have potential use as NIR shielding materials of low-cost and simple processes to be coated on an energy-efficient window as smart window coating in buildings and automotive thus reducing energy consumption, especially in air conditioning usage.


2015 ◽  
Vol 827 ◽  
pp. 43-48
Author(s):  
Annisa Noorhidayati ◽  
Mia Putri Rahmawati ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh

Transition metal ions (Co and Cr) doped ZnO nanoparticles supported on natural zeolite were synthesized using co-precipitation method. The synthesized samples were characterized by means of X-ray diffraction, energy dispersive X-ray, Fourier-transform infrared absorption, and UV-visible diffuse reflectance spectroscopy. The samples were further used as photocatalyst for degradation of methyl orange and methylene blue in aqueous solutions under UV light irradiation. The results showed that zeolite supported Cr-doped ZnO nanoparticles is more efficient compared with zeolite supported Co-doped ZnO nanoparticles. It is also revealed that zeolite supported samples possessed higher photocatalytic efficiency compared to bare samples.


Sign in / Sign up

Export Citation Format

Share Document