scholarly journals ZnO Nanosheets Exhibiting High UV Blocking Efficiency for Effective Application in Sunscreen

2020 ◽  
Vol 32 (7) ◽  
pp. 1809-1814
Author(s):  
Dojalisa Sahu ◽  
Nihar R. Panda ◽  
Debasrita Dash
Keyword(s):  
Uv Light ◽  
Zinc Acetate Dihydrate ◽  
Ammonium Hydroxide ◽  
Crystallographic Analysis ◽  
Wurtzite Phase ◽  
Uv Blocking ◽  
Porous Nanosheets ◽  
Zno Nanosheets ◽  
Photosensitive Layer ◽  
Blocking Property

Zinc oxide (ZnO) nanopowder has been prepared by wet chemical method and tested for its effective UV blocking property coated on photosensitive paper/fabric samples. Zinc acetate dihydrate and ammonium hydroxide were adopted as synthesis precursors. Phase and crystallographic analysis of the samples have been carried out by X-ray diffraction (XRD) and show that ZnO sample belong to hexagonal wurtzite phase without any impurity. Surface morphology of ZnO samples studied by field emission scanning electron microscopy (FESEM) shows the formation of nanosheets with porous structure. These porous nanosheets have surface area varying from 5000-30000 nm2 with thickness 10-15 nm. ZnO nanosheets on the photosensitive paper show UV absorbance around 300 nm as observed from the absorption spectrum. The reflectance spectrum of ZnO also shows its effectiveness in reflecting UV light in the region of 350-400 nm. The sun protection factors (SPF) and ultraviolet protection factors (UPF) calculated from the above studies are also encouraging implicating the use of ZnO in sunscreen. The above experiment is carried out by preparing a photosensitive layer similar to human skin. Similar experiment has also been carried out by treating ZnO nanosheets on fabric samples and studying its effectiveness for protection from UV rays.

Sethoxydim Response to Spray Carrier Chemical Properties and Environment

1994 ◽  
Vol 8 (3) ◽  
pp. 591-597 ◽  
Author(s):  
John D. Nalewaja ◽  
Robert Matysiak ◽  
Edward Szelezniak
Keyword(s):  
Low Temperature ◽  
Sodium Bicarbonate ◽  
Leaf Surface ◽  
Uv Light ◽  
Chemical Properties ◽  
Ammonium Hydroxide ◽  
Ammonium Salts ◽  
Uv Degradation ◽  
Solution Ph ◽  
Spray Solution

Experiments were conducted to determine the influence of spray carrier salts, UV light, and temperature on sethoxydim phytotoxicity to oat or yellow foxtail. Spray solution pH and ions present were both important to sethoxydim phytotoxicity to oat. Sodium and calcium salts were antagonistic to sethoxydim phytotoxicity only when the spray carrier pH exceeded 7. Ammonium salts and ammonium hydroxide were synergistic with sethoxydim, and the synergism was independent of spray solution pH. Ammonium sulfate, but not ammonium hydroxide, overcame sodium bicarbonate antagonism of sethoxydim. The antagonism of sethoxydim phytotoxicity by sodium bicarbonate was greatest in the presence of UV light and most pronounced when treated plants were exposed to mid-day sunlight. Sodium bicarbonate or low temperature may reduce the speed of sethoxydim absorption allowing for greater UV degradation of unabsorbed sethoxydim on the leaf surface.

Zinc Oxide Thin Film Synthesized by Sol-Gel Method

2020 ◽  
Vol 307 ◽  
pp. 51-57
Author(s):  
Amna Afiqah Nasution Hakim ◽  
Affa Rozana Abdul Rashid ◽  
N. Arsad ◽  
Aisyah Hanim Surani
Keyword(s):  
Thin Film ◽  
Uv Light ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Dip Coating ◽  
Oxide Thin Film ◽  
Gel Method ◽  
Sol Gel Method ◽  
Crystallite Sizes ◽  
Surface Morphologies

ZnO thin films have been prepared by the dip coating sol gel method. Zinc acetate dihydrate, 2-methoxyethanol and monoethanolamine (MEA) were used as precursor, solvent and stabilizer respectively. The synthesized sample was coated on glass substrate as the molarity of the solution was kept constant at 0.1 M. The structural properties and surface morphologies of ZnO thin film were characterized by XRD and FESEM. The optical properties such as transmittance, absorbance, reflectance and refractive index were studied by using UV-Vis. The functional group of the synthesized sample were verified by using FTIR. Average crystallite sizes of the samples were calculated by using Debye-Scherrer's formula. Next, ZnO is coated on POF in order to examine the reaction towards UV light.

scholarly journals Lignin as a UV Light Blocker—A Review

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1134 ◽  
Author(s):  
Hasan Sadeghifar ◽  
Arthur Ragauskas
Keyword(s):  
Molecular Weight ◽  
Functional Groups ◽  
Broad Spectrum ◽  
Uv Light ◽  
Complex Structure ◽  
Pulp And Paper ◽  
Transparent Film ◽  
Uv Blocking ◽  
Pulp And Paper Industries ◽  
Modified Forms

Lignin is the by-product of pulp and paper industries and bio-refining operations. It is available as the leading natural phenolic biopolymer in the market. It has chromophore functional groups and can absorb a broad spectrum of UV light in range of 250–400 nm. Using lignin as a natural ingredient in sunscreen cream, transparent film, paints, varnishes and microorganism protection has been actively investigated. Both in non-modified and modified forms, lignin provides enhancing UV protection of commercial products with less than a 10% blend with other material. In mixtures with other synthetic UV blockers, lignin indicated synergic effects and increased final UV blocking potential in compare with using only synthetic UV blocker or lignin. However, using lignin as a UV blocker is also challenging due to its complex structure, polydispersity in molecular weight, brownish color and some impurities that require more research in order to make it an ideal bio-based UV blocker.

UV-Blocking Property of Dumbbell-Shaped ZnO Crystallites on Cotton Fabrics

2005 ◽  
Vol 44 (11) ◽  
pp. 3926-3930 ◽  
Author(s):  
R. H. Wang ◽  
J. H. Xin ◽  
X. M. Tao
Keyword(s):  
Cotton Fabrics ◽  
Uv Blocking ◽  
Blocking Property

scholarly journals Hydrothermal Synthesis and Acetylene Sensing Properties of Variety Low Dimensional Zinc Oxide Nanostructures

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qu Zhou ◽  
Weigen Chen ◽  
Shudi Peng ◽  
Wen Zeng
Keyword(s):  
High Performance ◽  
Arc Discharge ◽  
Zinc Acetate Dihydrate ◽  
Zno Nanostructures ◽  
Zinc Oxide Nanostructures ◽  
Sensing Properties ◽  
Oxide Nanostructures ◽  
Zno Nanosheets ◽  
Low Dimensional ◽  
Screen Printing Technology

Various morphologies of low dimensional ZnO nanostructures, including spheres, rods, sheets, and wires, were successfully synthesized using a simple and facile hydrothermal method assisted with different surfactants. Zinc acetate dihydrate was chosen as the precursors of ZnO nanostructures. We found that polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), glycine, and ethylene glycol (EG) play critical roles in the morphologies and microstructures of the synthesized nanostructures, and a series of possible growth processes were discussed in detail. Gas sensors were fabricated using screen-printing technology, and their sensing properties towards acetylene gas (C2H2), one of the most important arc discharge characteristic gases dissolved in oil-filled power equipments, were systematically measured. The ZnO nanowires based sensor exhibits excellent C2H2sensing behaviors than those of ZnO nanosheets, nanorods, and nanospheres, indicating a feasible way to develop high-performance C2H2gas sensor for practical application.

scholarly journals Influence of Reaction Medium on CO2 Photocatalytic Reduction Yields Over Zns-MMT / Vliv Reakčního Prostření Na Výtěžky Fotokatalytické Redukce CO2 V Přítomnosti Zns-MMT

2012 ◽  
Vol 58 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Martin Reli ◽  
Marcel Šihor ◽  
Kamila Kočí ◽  
Petr Praus ◽  
Ondřej Kozák ◽  
...  
Keyword(s):  
Sodium Hydroxide ◽  
Gas Phase ◽  
Room Temperature ◽  
Uv Light ◽  
Ambient Pressure ◽  
Reaction Medium ◽  
Ammonium Hydroxide ◽  
Photocatalytic Reduction ◽  
Reaction Media ◽  
Better Than

Abstract The reduction of CO2 by photocatalysts is one of the most promising methods since CO2 can be reduced to useful compounds by irradiating it with UV light at room temperature and ambient pressure. The aim of this work was to assess the effect of a reaction media on CO2 photocatalytic reduction yields over ZnS nanoparticles deposited on montmorillonite (ZnS-MMT). Four different reaction media, such as NaOH, NaOH+Na2SO3 (1:1), NH4OH, NH4OH+Na2SO3 (1:1), were tested. The pure sodium hydroxide was better than ammonium hydroxide for the yields of the both gas phase (CH4 and CO) and liquid phase (CH3OH). The addition of Na2SO3 improved methanol yields due to the oxidation prevention of incipient methanol to carbon dioxide. The gas phase yields were decreased by the Na2SO3 addition. The best tested reaction medium for the photocatalytic reduction of CO2 was the solution of sodium hydroxide.

scholarly journals Facile Hydrothermal Synthesis of Two-Dimensional Porous ZnO Nanosheets for Highly Sensitive Ethanol Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Lai Van Duy ◽  
Nguyen Hong Hanh ◽  
Dang Ngoc Son ◽  
Pham Tien Hung ◽  
Chu Manh Hung ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Fast Response ◽  
Two Dimensional ◽  
Ethanol Sensor ◽  
X Ray ◽  
Transmission Electron ◽  
Porous Nanosheets ◽  
Composition And Structure ◽  
Zno Nanosheets

Two-dimensional porous ZnO nanosheets were synthesized by a facile hydrothermal method for ethanol gas-sensing application. The morphology, composition, and structure of the synthesized materials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and high-resolution transmission electron microcopy. Results showed that the synthesized ZnO materials were porous nanosheets with a smooth surface and a thickness of 100 nm and a large pore size of approximately 80 nm. The as-prepared nanosheets, which had high purity, high crystallinity, and good dispersion, were used to fabricate a gas sensor for ethanol gas detection at different operating temperatures. The porous ZnO nanosheet gas sensor exhibited a high response value of 21 toward 500 ppm ethanol at a working temperature of 400°C with a reversible and fast response to ethanol gas (12 s/231 s), indicating its potential application. We also discussed the plausible sensing mechanism of the porous ZnO nanosheets on the basis of the adopted ethanol sensor.

Feasibility of Hydrothermal Nitrogen Doping Process for Enhancing Visible Light Photocatalytic Activity of Metatitanic Acid Powder

2013 ◽  
Vol 761 ◽  
pp. 41-45
Author(s):  
Se Keun Park ◽  
Ji Eun Woo ◽  
Hyun Ho Shin
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Nitrogen Doping ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Ammonium Hydroxide ◽  
Nitrogen Sources ◽  
Wide Band ◽  
Metatitanic Acid ◽  
Sulfate Process

Wide band-gap photocatalyst is active only under UV light irradiation. Nitrogen doping into photocatalyst is able to extend the light absorption to the visible light region, allowing more solar energy to be utilized in photocatalytic applications. The hydrothermal process is widely applied for the preparation of nitrogen-doped TiO2. The hydrothermal method is attractive for its simplicity and environment friendly conditions. Metatitanic acid (MTA) is an industrially available intermediate product in sulfate process for TiO2production, which is mesoporous material with large specific surface area and pore volume. In this work, MTA powder was hydrothermally treated with three types of nitrogen sources (urea, hexamethylenetetramine, and ammonium hydroxide) and subsequently heat-treated in N2flow. The results of UV-Vis diffuse reflection spectra and XPS show that it is possible to dope the nitrogen dopant into MTA by the hydrothermal process and the post-heat treatment. Higher photocatalytic activity in photodegrading rhodamine B dye under visible light was obtained when processed in ammonium hydroxide (MTA-A), but weaker in the samples of urea (MTA-U) and hexamethylenetetramine (MTA-H).

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