scholarly journals Improving the Performance of Zinc Oxide Photocatalysts for Phenol Degradation through Addition of Lanthanum Species

2020 ◽  
Vol 23 (4) ◽  
pp. 109-116
Author(s):  
Wynona Agatha Nimpoeno ◽  
Hendrik Oktendy Lintang ◽  
Leny Yuliati
Keyword(s):  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Uv Light ◽  
Phenol Degradation ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Band Gap Energy ◽  
Fluorescence Emission Spectra ◽  
Green Approach ◽  
La Addition

One green approach to degrade organic pollutants, such as phenol, is through the photocatalytic reaction. Despite having large band gap energy, which is enough for phenol degradation, zinc oxide (ZnO) has low photocatalytic efficiency. In this study, ZnO was modified by lanthanum (La) species, and the improved photocatalytic activity was confirmed for degradation of phenol under visible and ultraviolet (UV) light irradiation. The ZnO and its modified photocatalysts were prepared by the hydrothermal method in the absence and presence of La species (0.01‒2 wt%). X-ray diffraction (XRD) patterns showed that the addition of La did not disturb the structure of ZnO, but slightly decreased the crystallite size. While the La addition up to 1 wt% did not affect the optical properties of the ZnO, the addition of 2 wt% La slightly red-shifted the absorption band edge of the ZnO. The Fourier-transform infrared (FT-IR) spectra showed La oxide formation observed at 515-540 cm-1 after 2 wt% La addition. Fluorescence emission spectra revealed that synthesized ZnO has oxygen vacancies at 558 nm, and the presence of 1 wt% La did not significantly affect the emission intensity. The photocatalytic activity of ZnO was influenced by the La addition, where the best performance was obtained on the ZnO with 1 wt% La. This study demonstrated that the optimum amount of La species could increase the performance of the ZnO.

scholarly journals A wavelength-dispersive instrument for characterizing fluorescence and scattering spectra of individual aerosol particles on a substrate

2016 ◽  
Vol 9 (8) ◽  
pp. 3987-3998 ◽  
Author(s):  
Donald R. Huffman ◽  
Benjamin E. Swanson ◽  
J. Alex Huffman
Keyword(s):  
Uv Light ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Aerosol Particles ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Advantages And Disadvantages ◽  
Biological Aerosols ◽  
Scattering Spectra

Abstract. We describe a novel, low-cost instrument to acquire both elastic and inelastic (fluorescent) scattering spectra from individual supermicron-size particles in a multi-particle collection on a microscope slide. The principle of the device is based on a slitless spectroscope that is often employed in astronomy to determine the spectra of individual stars in a star cluster but had not been applied to atmospheric particles. Under excitation, most commonly by either a 405 nm diode laser or a UV light-emitting diode (LED), fluorescence emission spectra of many individual particles can be determined simultaneously. The instrument can also acquire elastic scattering spectra from particles illuminated by a white-light source. The technique also provides the ability to detect and rapidly estimate the number fraction of fluorescent particles that could contaminate a collection of non-fluorescent material, even without analyzing full spectra. Advantages and disadvantages of using black-and-white cameras compared to color cameras are given. The primary motivation for this work has been to develop an inexpensive technique to characterize fluorescent biological aerosol particles, especially particles such as pollen and mold spores that can cause allergies. An example of an iPhone-enabled device is also shown as a means for collecting data on biological aerosols at lower cost or by utilizing citizen scientists for expanded data collection.

Tetrazole 5-Acetic Acid Catalyzed Synthesis and Photophysical Study of 2-Aryl-2,3-dihydroquinolin-4(1H)-ones

2019 ◽  
Vol 16 (3) ◽  
pp. 176-184
Author(s):  
Mohabul A. Mondal ◽  
Abdul Ashik Khan ◽  
Kanchan Mitra
Keyword(s):  
Acetic Acid ◽  
Uv Light ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Mechanistic Study ◽  
Fluorescence Emission Spectra ◽  
Initial Activation ◽  
Photophysical Study ◽  
Acid Catalyzed ◽  
Yellowish White

1H-Tetrazole 5-acetic acid (TAA) has been explored as a new organocatalyst for the synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones derivatives from 2’-aminoacetophenone under solventfree conditions. The method described herein is covenient and the catalyst could be reused. Mechanistic study of the reaction revealed that the reaction passing through initial activation of the aldehyde by the catalyst and the C-C bond formed through the intermolecular pathway. The synthesized compounds exhibit yellowish-white fluorescence when exposed to 350 nm UV light. Optical properties such as absorption and fluorescence emission spectra were monitored in methanol. Fluorescence emission properties in different solvents with different polarity indicate solvatochromic characteristics of the probes.

scholarly journals Temperature-dependent fluorescence emission spectra of acrylic (PMMA) and tetraphenyl butadiene (TPB) excited with UV light

2020 ◽  
Vol 15 (03) ◽  
pp. C03046-C03046 ◽  
Author(s):  
J.M. Corning ◽  
G.R. Araujo ◽  
P.C.F. Di Stefano ◽  
V. Pereymak ◽  
T. Pollmann ◽  
...  
Keyword(s):  
Uv Light ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Temperature Dependent ◽  
Fluorescence Emission Spectra

Optical Properties and Zinc Nitride Thin Films Prepared Using Magnetron Reactive Sputtering

2014 ◽  
Vol 940 ◽  
pp. 11-15
Author(s):  
Jun Qin Feng ◽  
Jun Fang Chen
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Sem Images ◽  
Fluorescence Emission Spectra ◽  
Glass Substrates ◽  
Zinc Nitride ◽  
Direct Band

Zinc nitride films were deposited by ion sources-assisted magnetron sputtering with the use of Zn target (99.99% purity) on 7059 glass substrates. The films were characterized by XRD, SEM and EDS, the results of which show that the polycrystalline zinc nitride thin film can be grown on the glass substrates, the EDS spectrum confirmed the chemical composition of the films and the SEM images revealed that the zinc nitride thin films have a dense structure. Ultraviolet-visible-near infrared spectrophotometer was used to study the transmittance behaviors of zinc nitride thin films, which calculated the optical band gap by Davis Mott model. The results of the fluorescence emission spectra show the zinc nitride would be a direct band gap semiconductor material.

Stress and Phase Transformation Phenomena in Oxide Films: Real-Time Spectroscopic Measurements

1992 ◽  
Vol 271 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Phase Transformation ◽  
Applied Pressure ◽  
Oxide Films ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Film Deposition ◽  
Optical Methods ◽  
Fluorescence Emission Spectra ◽  
Line Intensities ◽  
Deposition Parameters

ABSTRACTIn situ optical methods are reviewed for characterization of phase transformation processes and evaluation of residual stress in solution-deposited metastable oxide films. Such low density films most often are deposited as disordered phases making them prone to crystallization and attendant densification when subjected to increased temperature and/or applied pressure. Inherent stress imparted during film deposition and its evolution during the transformation are evaluated from phonon frequency shifts seen in Raman spectra (TiO2) or from changes in the laser-induced fluorescence emission spectra for films containing rare earth (Sm+3:Y3Al5O12) or transition metal (Cr+3 :Al2O3) dopants. The data in combination with measured increases in line intensities intrinsic to the evolving phase are used to follow crystallization processes in thin films. In general, film deposition parameters are found to influence the crystallite ingrowth kinetics and the magnitude of stress and stress relaxation in the film during the transformation. The utility of these methods to probe crystallization phenomena in oxide films will be addressed.

scholarly journals Fluorescence emission spectra of silver and silver/cobalt nanoparticles

2012 ◽  
Vol 19 (3) ◽  
pp. 943-947 ◽  
Author(s):  
Z. Parang ◽  
A. Keshavarz ◽  
S. Farahi ◽  
S.M. Elahi ◽  
M. Ghoranneviss ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Emission Spectra ◽  
Cobalt Nanoparticles ◽  
Fluorescence Emission Spectra

pH sensitive smart gels of cetylpyridinium chloride in binary solvent mixtures: phase behaviour, structure and composition

RSC Advances ◽  
2015 ◽  
Vol 5 (62) ◽  
pp. 50306-50311 ◽  
Author(s):  
Illa Ramakanth ◽  
Jaromír Pištora
Keyword(s):  
Cetylpyridinium Chloride ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Phase Behaviour ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
Gel Formation ◽  
Fluorescence Emission Spectra ◽  
Effect Of Ph ◽  
Binary Solvent Mixtures

Figure showing the effect of pH on CPC gel formation at 25 °C and fluorescence emission spectra of CPC solutions at pH ∼ 11.8.

scholarly journals The dependence of electrophoretic and spectroscopic properties of the pyruvate dehydrogenase complex on mono- and divalent ions.

1994 ◽  
Vol 41 (1) ◽  
pp. 63-72
Author(s):  
T Pawełczyk ◽  
R A Easom ◽  
M S Olson
Keyword(s):  
Ionic Strength ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Spectroscopic Properties ◽  
Uv Absorption ◽  
Divalent Ions ◽  
Fluorescence Emission Spectra ◽  
Dehydrogenase Complex

The effects of various mono- and divalent ions on the pyruvate dehydrogenase complex (PDC) were investigated. To determine the radius of PDC under various conditions a two-dimensional agarose gel electrophoresis technique was used. The radius of PDC cross-linked with glutaraldehyde at ionic strength 0.04 M was calculated to be 22.0 +/- 0.1 nm. The presence of K+, Na+ or HPO4(2-) prevented changes in electromobility and of the calculated radius of PDC induced by alteration in ionic strength. The fluorescence emission spectra of PDC depended on the ionic strength and monovalent cations. The fluorescence intensity of PDC increased in the presence of 80 mM K+, and decreased in the presence of 80 mM Na+ with no shift in the emission maximum wavelength. Changes in the ionic strength to which PDC was exposed resulted in alteration of the UV absorption spectra in the 230 nm region. These alterations were prevented by HPO4(2-), whereas Na+ or K+ ions had no effect on the UV absorption spectrum of PDC.

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