scholarly journals Photocatalytic Degradation of 2-Chlorophenol Using Ag-Doped TiO2Nanofibers and a Near-UV Light-Emitting Diode System

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ju-Young Park ◽  
In-Hwa Lee
Keyword(s):  
Phase Transformation ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Order Equation ◽  
Light Emitting ◽  
First Order ◽  
Uv Led ◽  
Diode System

This report investigated the photocatalytic degradation of 2-chlorophenol using TiO2nanofibers and Ag-doped TiO2nanofibers, synthesized using the sol-gel and electrospinning techniques, and an ultraviolet light-emitting diode (UV-LED) system as a UV light source. The crystallite size of the Ag-doped TiO2nanofibers was smaller than that of the TiO2nanofibers, because silver retrained phase transformation not only controls the phase transformation but also inhibits the growth of anatase crystallites. The activation energies for the grain growth of the TiO2nanofibers and the Ag-doped TiO2nanofibers were estimated to be 20.84 and 27.01 kJ/mol, respectively. The photocatalytic degradation rate followed a pseudo-first-order equation. The rate constants (k) of the TiO2nanofibers and the Ag-doped TiO2nanofibers were 0.056 and 0.144 min−1, respectively.

Ultraviolet Light Stable and Transparent Sol–Gel Methyl Siloxane Hybrid Material for UV Light-Emitting Diode (UV LED) Encapsulant

2015 ◽  
Vol 7 (2) ◽  
pp. 1035-1039 ◽  
Author(s):  
Jun-young Bae ◽  
YongHo Kim ◽  
HweaYoon Kim ◽  
YuBae Kim ◽  
Jungho Jin ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Hybrid Material ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Light Emitting ◽  
Uv Led ◽  
Siloxane Hybrid Material

Origins and suppressions of parasitic emissions in ultraviolet light-emitting diode structures

2010 ◽  
Vol 25 (6) ◽  
pp. 1037-1040 ◽  
Author(s):  
Weihuang Yang ◽  
Shuping Li ◽  
Hangyang Chen ◽  
Dayi Liu ◽  
Junyong Kang
Keyword(s):  
Quantum Wells ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Force Microscopy ◽  
Uv Led ◽  
Hole Blocking Layer ◽  
To Come ◽  
P Type

The AlGaN-based ultraviolet (UV) light-emitting diode (LED) structures with AlN as buffer were grown on sapphire substrate by metalorganic vapor-phase epitaxy (MOVPE). A series of cathodoluminescence (CL) spectra were measured from the cross section of the UV-LED structure using point-by-point sampling to investigate the origins of the broad parasitic emissions between 300 and 400 nm, and they were found to come from the n-type AlGaN and AlN layers rather than p-type AlGaN. The parasitic emissions were effectively suppressed by adding an n-type AlN as the hole-blocking layer. Electroluminescence (EL) and atomic force microscopy (AFM) measurements have revealed that the interface abruptness and crystalline quality of the UV-LED structure are essential for the achievement of the EL emissions from the multiple quantum wells (MQWs).

scholarly journals UV light-emitting diode (UV-LED) at 265 nm as a potential light source for disinfecting human platelet concentrates

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251650
Author(s):  
Tomoya Hayashi ◽  
Kumiko Oguma ◽  
Yoshihiro Fujimura ◽  
Rika A. Furuta ◽  
Mitsunobu Tanaka ◽  
...  
Keyword(s):  
Platelet Transfusion ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Platelet Concentrates ◽  
Platelet Surface ◽  
Light Emitting ◽  
Peak Emission Wavelength ◽  
Uv Led ◽  
Bacterial Transmission ◽  
Induced Aggregation

The risk of sepsis through bacterial transmission is one of the most serious problems in platelet transfusion. In processing platelet concentrates (PCs), several methods have been put into practice to minimize the risk of bacterial transmission, such as stringent monitoring by cultivation assays and inactivation treatment by photoirradiation with or without chemical agents. As another potential option, we applied a light-emitting diode (LED) with a peak emission wavelength of 265 nm, which has been shown to be effective for water, to disinfect PCs. In a bench-scale UV-LED exposure setup, a 10-min irradiation, corresponding to an average fluence of 9.2 mJ/cm2, resulted in >2.0 log, 1.0 log, and 0.6 log inactivation (mean, n = 6) of Escherichia coli, Staphylococcus aureus, and Bacillus cereus, respectively, in non-diluted plasma PCs. After a 30-min exposure, platelet counts decreased slightly (18 ± 7%: mean ± SD, n = 7); however, platelet surface expressions of CD42b, CD61, CD62P, and PAC-1 binding did not change significantly (P>0.005), and agonist-induced aggregation and adhesion/aggregation under flow conditions were well maintained. Our findings indicated that the 265 nm UV-LED has high potential as a novel disinfection method to ensure the microbial safety of platelet transfusion.

scholarly journals Photocatalytic Oxidative Degradation of Carbamazepine by TiO2 Irradiated by UV Light Emitting Diode

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 540 ◽  
Author(s):  
Zhilin Ran ◽  
Yuanhang Fang ◽  
Jian Sun ◽  
Cong Ma ◽  
Shaofeng Li
Keyword(s):  
Photocatalytic Degradation ◽  
Uv Light ◽  
Reaction System ◽  
Reference Method ◽  
Degradation Efficiency ◽  
Mixed Phase ◽  
Light Emitting ◽  
Led Light ◽  
Irradiation Intensity ◽  
Uv Led

Here, ultraviolet light-emitting diodes (UV-LED) combined with TiO2 was used to investigate the feasibility of carbamazepine (CBZ) degradation. The effects of various factors, like crystal form of the catalyst (anatase, rutile, and mixed phase), mass concentration of TiO2, wavelength and irradiation intensity of the UV-LED light source, pH of the reaction system, and coexisting anions and cations, on the photocatalytic degradation of CBZ were studied. The mixed-phase (2.8 g/L) showed the best degradation efficiency at 365 nm among three kinds of TiO2, wherein CBZ (21.1 µM) was completely oxidized within 1 h. The results of batch experiments showed that: (i) CBZ degradation efficiency under UV-LED light at 365 nm was higher than 275 nm, due to stronger penetrability of 365 nm light in solution. (ii) The degradation efficiency increased with increase in irradiation intensity and pH, whereas it decreased with increase in initial CBZ concentration. (iii) The optimal amount of mixed-phase TiO2 catalyst was 2.8 g/L and excessive catalyst decreased the rate. (iv) The co-existence of CO32−, HCO3−, and Fe3+ ions in water significantly accelerated the degradation rate of photocatalytic CBZ, whereas Cu2+ ions strongly inhibited the degradation process of CBZ. ·OH was found to be the main active species in the UV-LED photocatalytic degradation of CBZ. UV-LED is more environmentally friendly, energy efficient, and safer, whereas commercial TiO2 is economical and readily available. Therefore, this study provides a practically viable reference method for the degradation of pharmaceuticals and personal care products (PPCPs).

scholarly journals Development of a Toluene Detector Based on Deep UV Absorption Spectrophotometry Using Glass and Aluminum Capillary Tube Gas Cells with a LED Source

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 193 ◽  
Author(s):  
Sulaiman Khan ◽  
David Newport ◽  
Stéphane Le Calvé
Keyword(s):  
Gas Flow ◽  
Capillary Tube ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Uv Absorption ◽  
Glass Capillary ◽  
Light Emitting ◽  
Uv Led ◽  
3D Printed ◽  
Deep Uv

A simple deep-ultraviolet (UV) absorption spectrophotometer based on ultraviolet light-emitting diode (UV LED) was developed for the detection of air-borne toluene with a good sensitivity. A fiber-coupled deep UV-LED was employed as a light source, and a spectrometer was used as a detector with a gas cell in between. 3D printed opto-fluidics connectors were designed to integrate the gas flow with UV light. Two types of hollow core waveguides (HCW) were tested as gas cells: a glass capillary tube with aluminum-coated inner walls and an aluminum capillary tube. The setup was tested for different toluene concentrations (10–100 ppm), and a linear relationship was observed with sensitivities of 0.20 mA·U/ppm and 0.32 mA·U/ppm for the glass and aluminum HCWs, respectively. The corresponding limits of detection were found to be 8.1 ppm and 12.4 ppm, respectively.

scholarly journals Design of a Secondary Freeform Lens of UV LED Mosquito-Trapping Lamp for Enhancing Trapping Efficiency

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 335 ◽  
Author(s):  
Wei-Hsiung Tseng ◽  
Diana Juan ◽  
Wei-Cheng Hsiao ◽  
Cheng-Han Chan ◽  
Hsin-Yi Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Intensity Distribution ◽  
Light Emitting Diode ◽  
Trapping Efficiency ◽  
Axially Symmetric ◽  
Light Intensity Distribution ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Freeform Lens

In this study, our proposed ultraviolet light-emitting diode (UV LED) mosquito-trapping lamp is designed to control diseases brought by insects such as mosquitoes. In order to enable the device to efficiently catch mosquitoes in a wider area, a secondary freeform lens (SFL) is designed for UV LED. The lens is mounted on a 3 W UV LED light bar as a mosquito-trapping lamp of the new UV LED light bar module to achieve axially symmetric light intensity distribution. The special SFL is used to enhance the trapping capabilities of the mosquito-trapping lamp. The results show that when the secondary freeform surface lens is applied to the experimental outdoor UV LED mosquito-trapping lamp, the trapping range can be expanded to 100π·m2 and the captured mosquitoes increased by about 300%.

scholarly journals Photocatalytic Degradation of Sulfolane Using a LED-Based Photocatalytic Treatment System

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 624
Author(s):  
Sripriya Dharwadkar ◽  
Linlong Yu ◽  
Gopal Achari
Keyword(s):  
Photocatalytic Degradation ◽  
Oil And Gas ◽  
Light Emitting Diode ◽  
Tap Water ◽  
Aqueous Media ◽  
Ultrapure Water ◽  
Light Emitting ◽  
Degradation Rates ◽  
Reduced Graphene ◽  
The Impact

Sulfolane is an emerging industrial pollutant detected in the environments near many oil and gas plants in North America. So far, numerous advanced oxidation processes have been investigated to treat sulfolane in aqueous media. However, there is only a few papers that discuss the degradation of sulfolane using photocatalysis. In this study, photocatalytic degradation of sulfolane using titanium dioxide (TiO2) and reduced graphene oxide TiO2 composite (RGO-TiO2) in a light-emitting diode (LED) photoreactor was investigated. The impact of different waters (ultrapure water, tap water, and groundwater) and type of irradiation (UVA-LED and mercury lamp) on photocatalytic degradation of sulfolane were also studied. In addition, a reusability test was conducted for the photocatalyst to examine the degradation of sulfolane in three consecutive cycles with new batches of sulfolane-contaminated water. The results show that LED-based photocatalysis was effective in degrading sulfolane in waters even after three photocatalytic cycles. UVA-LEDs displayed more efficient use of photon energy when compared with the mercury lamps as they have a narrow emission spectrum coinciding with the absorption of TiO2. The combination of UVA-LED and TiO2 yielded better performance than UVA-LED and RGO-TiO2 for the degradation of sulfolane. Much lower sulfolane degradation rates were observed in tap water and groundwater than ultrapure water.

Sign in / Sign up

Export Citation Format

Share Document