scholarly journals Synthesis of photocatalytic zinc oxide nanoflowers using Peltophorum pterocarpum pod extract and their characterization

2021 ◽  
Author(s):  
Ramesh Vinayagam ◽  
Shraddha Pai ◽  
Gokulakrishnan Murugesan ◽  
Thivaharan Varadavenkatesan ◽  
Raja Selvaraj
Keyword(s):  
Zinc Oxide ◽  
Optical Band Gap ◽  
Kinetic Constant ◽  
High Specific Surface Area ◽  
Order Equation ◽  
Blue Dye ◽  
Sem Images ◽  
Wurtzite Phase ◽  
First Order ◽  
Bet Analysis

AbstractZinc oxide nanoflowers (ZnONFs) were prepared by employing the pod extract of Peltophorum pterocarpum as a green resource and characterized by various methods. UV–vis spectrum displayed a peak at 361 nm which confirmed the formation of ZnO nanoparticles. The optical band gap was calculated as 3.43 eV. FE-SEM images exposed the flower-like morphology and EDX portrayed strong signals for Zn and O. XRD studies substantiated signature peaks for the wurtzite phase of ZnONFs and the lattice parameters matched well with the literature. Mesoporous nature was confirmed by BET analysis which yielded a high specific surface area of 19.61 m2/g. FTIR bands at 420.48 and 462.92 cm−1affirmed the Zn and O bonding vibrations. The photocatalytic potential of the ZnONFs was successfully examined for the removal of methylene blue dye under natural solar light. The experimental data were fitted to Langmuir–Hinshelwood’s first-order equation and the kinetic constant was calculated as 0.0114 min–1.

Structural Evolution of Nickel Doped Zinc Oxide Nanostructures

2013 ◽  
Vol 1551 ◽  
pp. 47-52 ◽  
Author(s):  
Navendu Goswami ◽  
Anshuman Sahai
Keyword(s):  
Raman Spectroscopy ◽  
Zinc Oxide ◽  
Structural Evolution ◽  
Precipitation Method ◽  
Zinc Oxide Nanostructures ◽  
Ni Doping ◽  
Sem Images ◽  
Wurtzite Phase ◽  
Oxide Nanostructures ◽  
Doped Zno

ABSTRACTIn this article, structural evolution in nickel doped zinc oxide nanostructures is reported. The ZnO nanostructures are synthesized with 1-10% of Ni doping adopting a chemical precipitation method. The undoped and doped nanostructures thus prepared, were systematically investigated employing X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM/SEM), Fourier transform infrared (FTIR) and micro-Raman spectroscopy (μRS). The identification of wurtzite phase and determination of lattice parameters of Ni doped ZnO nanocrystallites is ascertained through XRD analysis. TEM/SEM images reveal the structural alteration of ZnO with variation of Ni doping concentrations. The study of vibrational modes of nanostructures at different stages of structural transformation, as performed through FTIR and Raman spectroscopy, assist in deciphering the crucial role of Ni doping concentration in gradual evolution of nickel doped ZnO structure from nanoparticles to nanorods.

scholarly journals Rootlike Morphology of ZnO:Al Thin Film Deposited on Amorphous Glass Substrate by Sol-Gel Method

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Heri Sutanto ◽  
Sufwan Durri ◽  
Singgih Wibowo ◽  
Hady Hadiyanto ◽  
Eko Hidayanto
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Glass Substrate ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Spray Coating ◽  
Hexagonal Structure ◽  
Zno Films ◽  
Sem Images

Zinc oxide (ZnO) and aluminum doped zinc oxide (ZnO:Al) thin films have been deposited onto a glass substrate by sol-gel spray coating method at atmospheric pressure. X-ray diffractometer (XRD), scanning electron microscopy (SEM), and UV-Vis spectrophotometer have been used to characterize the films. XRD spectra indicated that all prepared thin films presented the wurtzite hexagonal structure. SEM images exhibited rootlike morphology on the surface of thin films and the shortest root diameter was about 0.219 μm. The UV-Vis absorption spectra exhibited the absorption edges that were slightly shifted to the lower wavelength. From this result, the incorporation of aluminum into the ZnO involved a slight increase in the optical band-gap of films. The optical bands of films were 3.102 eV, 3.115 eV, 3.118 eV, 3.115 eV, 3.109 eV, and 3.109 eV for ZnO, ZnO:Al 2%, ZnO:Al 4%, ZnO:Al 6%, ZnO:Al 8%, and ZnO:Al 10%, respectively. Increase of Al doping concentration in ZnO films contributed to the increase of their optical band-gap which can be explained by the Burstein-Moss effect.

Photocatalytic degradation of methylene blue dye by porous zinc oxide nanofibers prepared via electrospinning: when defects become merits

2021 ◽  
pp. 149830
Author(s):  
Fabiola Pantò ◽  
Zainab Dahrouch ◽  
Abhirup Saha ◽  
Salvatore Patanè ◽  
Saveria Santangelo ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Zinc Oxide ◽  
Photocatalytic Degradation ◽  
Blue Dye ◽  
Methylene Blue Dye

scholarly journals Equilibrium and Kinetic Study of Anionic and Cationic Pollutants Remediation by Limestone–Chitosan–Alginate Nanocomposite from Aqueous Solution

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2586
Author(s):  
Inas A. Ahmed ◽  
Ahmed H. Ragab ◽  
Mohamed A. Habila ◽  
Taghrid S. Alomar ◽  
Enas H. Aljuhani
Keyword(s):  
Physical Adsorption ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Sem Images ◽  
Bet Analysis ◽  
Adsorption Processes ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Multilayer Formation

In this work, low-cost and readily available limestone was converted into nanolimestone chitosan and mixed with alginate powder and precipitate to form a triple nanocomposite, namely limestone—chitosan–alginate (NLS/Cs/Alg.), which was used as an adsorbent for the removal of brilliant green (BG) and Congo red (CR) dyes in aqueous solutions. The adsorption studies were conducted under varying parameters, including contact time, temperature, concentration, and pH. The NLS/Cs/Alg. was characterized by SEM, FTIR, BET, and TEM techniques. The SEM images revealed that the NLS/Cs/Alg. surface structure had interconnected pores, which could easily trap the pollutants. The BET analysis established the surface area to be 20.45 m2/g. The recorded maximum experimental adsorption capacities were 2250 and 2020 mg/g for CR and BG, respectively. The adsorption processes had a good fit to the kinetic pseudo second order, which suggests that the removal mechanism was controlled by physical adsorption. The CR and BG equilibrium data had a good fit for the Freundlich isotherm, suggesting that adsorption processes occurred on the heterogeneous surface with a multilayer formation on the NLS/Cs/Alg. at equilibrium. The enthalpy change (ΔH0) was 37.7 KJ mol−1 for CR and 8.71 KJ mol−1 for BG, while the entropy change (ΔS0) was 89.1 J K−1 mol−1 for CR and 79.1 J K−1 mol−1 BG, indicating that the adsorption process was endothermic and spontaneous in nature.

scholarly journals ON SUPERLUMINAL FERMIONS WITHIN THE SECOND DERIVATIVE EQUATION

2012 ◽  
Vol 27 (14) ◽  
pp. 1250081 ◽  
Author(s):  
S. I. KRUGLOV
Keyword(s):  
Energy Momentum Tensor ◽  
Canonical Quantization ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Order Equation ◽  
Quantum Mechanical ◽  
Projection Operators ◽  
The Novel ◽  
First Order ◽  
Electromagnetic Interactions

We postulate the second-order derivative equation with four parameters for spin-1/2 fermions possessing two mass states. For some choice of parameters fermions propagate with the superluminal speed. Thus, the novel tachyonic equation is suggested. The relativistic 20-component first-order wave equation is formulated and projection operators extracting states with definite energy and spin projections are obtained. The Lagrangian formulation of the first-order equation is presented and the electric current and energy–momentum tensor are found. The minimal and nonminimal electromagnetic interactions of fermions are considered and Schrödinger's form of the equation and the quantum-mechanical Hamiltonian are obtained. The canonical quantization of the field in the first-order formalism is performed and we find the vacuum expectation of chronological pairing of operators.

Zinc oxide incorporated carbon nanotubes or graphene oxide nanohybrids for enhanced sonophotocatalytic degradation of methylene blue dye

2019 ◽  
Vol 487 ◽  
pp. 539-549 ◽  
Author(s):  
Mohamed Mokhtar Mohamed ◽  
Mohamed A. Ghanem ◽  
Mohamed Khairy ◽  
Eman Naguib ◽  
Nouf H. Alotaibi
Keyword(s):  
Carbon Nanotubes ◽  
Methylene Blue ◽  
Zinc Oxide ◽  
Graphene Oxide ◽  
Blue Dye ◽  
Methylene Blue Dye

scholarly journals Design and Synthesis of Novel 2D Porous Zinc Oxide-Nickel Oxide Composite Nanosheets for Detecting Ethanol Vapor

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1989
Author(s):  
Yuan-Chang Liang ◽  
Yen-Cheng Chang ◽  
Wei-Cheng Zhao
Keyword(s):  
Zinc Oxide ◽  
Nickel Oxide ◽  
Active Sites ◽  
Gas Sensing ◽  
Ethanol Vapor ◽  
Gas Diffusion ◽  
High Specific Surface Area ◽  
Sputtering Deposition ◽  
Vapor Sensing ◽  
Sensing Performance

The porous zinc oxide-nickel oxide (ZnO-NiO) composite nanosheets were synthesized via sputtering deposition of NiO thin film on the porous ZnO nanosheet templates. Various NiO film coverage sizes on porous ZnO nanosheet templates were achieved by changing NiO sputtering duration in this study. The microstructures of the porous ZnO-NiO composite nanosheets were investigated herein. The rugged surface feature of the porous ZnO-NiO composite nanosheets were formed and thicker NiO coverage layer narrowed the pore size on the ZnO nanosheet template. The gas sensors based on the porous ZnO-NiO composite nanosheets displayed higher sensing responses to ethanol vapor in comparison with the pristine ZnO template at the given target gas concentrations. Furthermore, the porous ZnO-NiO composite nanosheets with the suitable NiO coverage content demonstrated superior gas-sensing performance towards 50–750 ppm ethanol vapor. The observed ethanol vapor-sensing performance might be attributed to suitable ZnO/NiO heterojunction numbers and unique porous nanosheet structure with a high specific surface area, providing abundant active sites on the surface and numerous gas diffusion channels for the ethanol vapor molecules. This study demonstrated that coating of NiO on the porous ZnO nanosheet template with a suitable coverage size via sputtering deposition is a promising route to fabricate porous ZnO-NiO composite nanosheets with a high ethanol vapor sensing ability.

On the Vibration of a Rotating Disk

1972 ◽  
Vol 39 (4) ◽  
pp. 1143-1144 ◽  
Author(s):  
S. Barasch ◽  
Y. Chen
Keyword(s):  
Approximate Calculation ◽  
Initial Conditions ◽  
Rotating Disk ◽  
Equation Of Motion ◽  
Outer Radius ◽  
Order Equation ◽  
System Of Differential Equations ◽  
Fourth Order Equation ◽  
First Order ◽  
Inner Radius

The equation of motion of a rotating disk, clamped at the inner radius and free at the outer radius, is solved by reducing the fourth-order equation of motion to a set of four first-order equations subject to arbitrary initial conditions. A modified Adams’ method is used to numerically integrate the system of differential equations. Results show that Lamb-Southwell’s approximate calculation of the frequency is justified.

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