• Title/Summary/Keyword: $UV/O_2$

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SnO2-Embedded Transparent UV Photodetector (SnO2 기반의 투명 UV 광 검출기)

  • Lee, Gyeong-Nam;Park, Wang-Hee;Kim, Joondong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.12
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    • pp.806-811
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    • 2017
  • An all-transparent ultraviolet (UV) photodetector was fabricated by structuring $p-NiO/n-SnO_2/ITO$ on a glass substrate. $SnO_2$ is an important semiconductor material because of its large bandgap, high electron mobility, high transmittance (as high as 80% in the visible range), and high stability under UV light. For these reasons, $SnO_2$ is suitable for a range of applications that involve UV light. In order to form a highly transparent p-n junction for UV detection, $SnO_2$ was deposited onto a device containing NiO as a high-transparent metal conductive oxide for UV detection. We demonstrated that all-transparent UV photodetectors based on $SnO_2$ could provide a definitive photocurrent density of $4nA\;cm^{-2}$ at 0 V under UV light (365 nm) and a low saturation current density of $2.02nA{\times}cm^{-2}$. The device under UV light displayed fast photoresponse with times of 31.69 ms (rise-time) and 35.12 ms (fall-time) and a remarkable photoresponse ratio of 69.37. We analyzed the optical and electrical properties of the $NiO/SnO_2$ device. We demonstrated that the excellent properties of $SnO_2$ are valuable in transparent photoelectric device applications, which can suggest various routes for improving the performance of such devices.

Effects of Advanced Oxidation of Penicillin on Biotoxicity, Biodegradability and Subsequent Biological Treatment (고도산화공정 처리가 페니실린의 생독성, 생분해도 및 생물학적 분해에 미치는 영향)

  • Luu, Huyen Trang;Minh, Dang Nhat;Lee, Kisay
    • Applied Chemistry for Engineering
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    • v.29 no.6
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    • pp.690-695
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    • 2018
  • Advanced oxidation processes (AOPs) composed of O3 and UV were applied to degrade penicillin (PEN). The degradation efficiency was evaluated in terms of changes in the absorbance (ABS) and total organic carbon (TOC). The combination of $O_3/H_2O_2/UV$ and $O_3/UV$ showed the best performance for the reduction of ABS (100% for 9 min) and TOC (70% for 60 min) values, although the mineralization was uncompleted under the experimental condition in this study. The change in biotoxicy was monitored with Escherichia coli susceptibility and Vibrio fischeri biofluorescence. The E. coli susceptibility was eliminated completely for 9 min by $O_3/UV$, and the toxicity to V. fischeri biofluorescence was 57% reduced by $O_3/H_2O_2/UV$. For the ultimate treatment of PEN, it is suggested that an AOP using $O_3/UV$ is followed by biological treatment, utilizing the enhanced biodegradability by the AOP. During 30 min of $O_3/UV$ treatment, the $BOD_5/COD$ ratio as an indication of biodegradability showed about 4-fold increment, compared to that of using a non-treated sample. TOC removal rate for AOP-pretreated PEN wastewater increased 55% compared to that of using the non-pretreated one through an aerobic biological treatment by Pseudomonas putida for artificial wastewater containing 20 mg/L of PEN. In conclusion, $O_3/UV$ process is recommended as a pretreatment step prior to an aerobic biological process to improve the ultimate degradation of penicillin.

A Study on the Swine Wastewater Treatment Using UV/TiO2/H2O2 (UV/TiO2/H2O2를 이용한 축산폐수처리에 대한 연구)

  • Kim, Chang-Kyun;Chung, Ho-Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.3B
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    • pp.321-327
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    • 2006
  • This study was performed to provide basic information for evaluating the efficiency and applicable extent of photocatalysis for the treatment of swine wastewater. Acid area was more efficient than neutral and alkalic areas in wastewater treatment, and level of pH3 was the most effective and the treatment efficiency continually increased as the amount of photocatalyst was increased. When the photocatalyst was increased, $TCOD_{Mn}$ was removed faster than chromaticity. Pollutants were more effectively eliminated with both UV light illumination and $TiO_2$ than with either UV or $TiO_2$ alone. The removal efficiency was increased with the addition of $H_2O_2$ as an oxidant, but the removal efficiency was decreased with over an dosage of $H_2O_2$. The optimal dosage of $H_2O_2$ was 200 mg/L. Continuous injection of $H_2O_2$ was required for effective oxidation.

Decolorization of Rhodamine B by Photo-Fenton Oxidation (광-펜톤 산화반응을 이용한 Rhodamine B의 탈색)

  • Park, Young-Seek
    • Journal of Korean Society on Water Environment
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    • v.23 no.2
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    • pp.274-280
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    • 2007
  • The photochemical decolorization of Rhodamine B (RhB) in water has been carried out by photo-Fenton process. The effect of applied $H_2O_2$, $Fe^{2+}$ dose, solution pH and UV dose have been studied. The influence of constituent processes of photo-Fenton such as UV, $H_2O_2$ and Fenton has been investigated. Comparison of RhB removal was made between the photo-Fenton and $UV/H_2O_2$ process. The results obtained showed that the optimum dosage of $Fe^{2+}$ and $H_2O_2$ were 0.0031 mmol and 0.625 mol, respectively. pH 3 is found to be the optimum pH of for photo-Fenton process. pH and UV dose strongly influenced the decolorization of RhB in photo-Fenton process. The photo-Fenton and $UV/H_2O_2$ processes showed similar decolorization and seem to be appropriate for the decolorization of dye wastewater.

Effect of the Introduction of UV Irradiation on Crystallization of Sr0.9Bi2.1Ta2O9 Thin Films by Sol-gel Method (UV노광 공정 도입이 Sol-gel 법으로 제조된 Sr0.9Bi2.1Ta2O9박막의 결정화에 미치는 영향)

  • 최병옥;김병호
    • Journal of the Korean Ceramic Society
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    • v.40 no.2
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    • pp.184-190
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    • 2003
  • $Sr_{0.9}Bi_{2.1}Ta_2O_9$thin films were deposited on $IrO_2$ electrode by spin coating method using photosensitive sol-gel solution. To ensure the UV-exposure effect on SBT thin films, UV irradiated films and non-UV irradiated films were analyzed by XRD, SEM. As a result, UV-irradiation on SBT thin films promoted grain growth of SBT compared with no UV irradiation. In case of the UV irradiated films annealed at$740{\circ}C$for 1 h in an oxygen ambient, the 2Pr value and Pr/Ps at${pm}5$V were$11.48{mu}C/cm^2$and 0.53, respectively. 2Pr values of the UV irradiated SBT thin films at$660-740{circ}C were approximately 12% higher than those of non-UV irradiated thin films.

Deconvolution of UV Spectrum for Selective Measurement of $ClO_2$ Concentration Quantitatively in Solution Containing Various Chlorine Species (다양한 염소 종이 함유된 수용액에서 자외선 흡수 파장 분해법을 이용한 이산화염소 선별 정량 분석)

  • Byun, Youngchul;Kim, Jaehoon;Jang, Yumi;Lee, Kiman;Lee, Jae Myeong;Shin, Dong Nam
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.11
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    • pp.743-750
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    • 2012
  • An ultraviolet (UV) absorption method has a difficulty to analyze $ClO_{2(aq)}$ in solutions containing various chlorine species because UV spectrum of $ClO_{2(aq)}$ overlaps with other chlorine-containing species. This study has proposed the deconvolution method of UV spectrum to analyze $ClO_{2(aq)}$ concentration quantitatively in solution containing various chlorine species. We compared results obtained from UV deconvolution method with titration method. Good agreement of $ClO_{2(aq)}$ concentration between them has been shown in about 10%. This result informs us that the deconvolution method of UV spectrum could be a feasible for the analysis of $ClO_{2(aq)}$ in solution containing various chlorine species.

Removal of COD and Color from Anaerobic Digestion Effluent of Livestock Wastewater by Advanced Oxidation Using Microbubbled Ozone (마이크로버블 오존 고도산화를 이용한 축산폐수 혐기소화 배출수의 COD와 색도의 제거)

  • Lee, Inkyu;Lee, Eunyoung;Lee, Hyejung;Lee, Kisay
    • Applied Chemistry for Engineering
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    • v.22 no.6
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    • pp.617-622
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    • 2011
  • Ozone-based advanced oxidation was applied for the treatment of anaerobic digestion effluent of livestock wastewater. Initial COD and color value were 930 mg/L and 0.04, respectively, and the 1/10-diluted wastewater was used for the study. The treatment characteristics were compared between the conventionally generated ozone ($105{\mu}m$) and microbubbled ozone ($13{\mu}m$). The use of microbubbled ozone improved the removal of chemical oxygen demand (COD) and color by 85% and 26%, respectively, compared with the conventionally bubbled ozone. The application of microbubbled $O_3/UV$, $O_3/H_2O_2$, $O_3/UV/H_2O_2$ combinations resulted in 5~10% higher color removal than ozone alone, which implies that the contribution of UV or $H_2O_2$ is not significant in color removal. On the other hand, COD removal could be increased two folds compared with ozone alone through $O_3/UV/H_2O_2$ combination. The contribution of $H_2O_2$ was bigger than UV for COD removal with microbubbled ozone. Due to the enhancement of dissolved ozone and radical activity, the microbubbling enabled us to additional COD removal even after stopping ozone supply in the presence of UV or $H_2O_2$.

Advanced Oxidation Processes of Secondary Effluent for Reuse (재사용을 위한 하수처리장 방류수의 고급산화처리)

  • 조일형;송경석;성기석;정문호;이홍근;조경덕
    • Journal of Environmental Health Sciences
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    • v.26 no.3
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    • pp.61-68
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    • 2000
  • The use of photo-catalytic processes in pollution abatement and resource has a significant economic importance. Therefore, the applications of photochemical oxidation of secondary effluent driven by UV, TiO2, TiO2/UV, H2O2/UV and TiO2/H2O2/UV, have been investigated in order to treat the secondary effluent from municipal sewage. Various experimental parameters such as BOD, CODcr, Nurbidity, total P, and SPC were examined in each photo-catalytic reaction system. The results showed that the application of single oxidant such as UV, TiO2 only has a minor effect on parameters reduction (CODcr, BOD, etc) to treat the secondary effluent, whereas the combinations of oxidants increase the removal efficiency. The best removal efficiency in every parameters was achieved by the combination of TiO2, H2O2 and UV. It was also found that the optimum amount of TiO2 for the treatment was 1g/ι to achieve water reuse standard. From the results, the photocatalytic reaction system can be an alternative as a post-treatment to treat the secondary effluent from municipal sewage.

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Fabrication of ZnO inorganic thin films by using UV-enhanced Atomic Layer Deposition

  • Song, Jong-Su;Yun, Hong-Ro;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.312.1-312.1
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    • 2016
  • We have deposited ZnO thin films by ultraviolet (UV) enhanced atomic layer deposition using diethylznic (DEZ) and water (H2O) as precursors with UV light. The atomic layer deposition relies on alternating dose of the precursor on the surface and subsequent chemisorption of the precursors with self-limiting growth mechanism. Though ALD is useful to deposition conformal and precise thin film, the surface reactions of the atomic layer deposition are not completed at low temperature in many cases. In this experiment, we focused on the effects of UV radiation during the ALD process on the properties of the inorganic thin films. The surface reactions were found to be complementary enough to yield uniform inorganic thin films and fully react between DEZ and H2O at the low temperature by using UV irradiation. The UV light was effective to obtain conductive ZnO film. And the stability of TFT with UV-enhanced ZnO was improved than ZnO by thermal ALD method. High conductive UV-enhanced ZnO film have the potential to applicability of the transparent electrode.

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SPF Measurement and Cytotoxicity of Sunscreen Agents in Cosmetic (화장품에서 UV 차단제의 피부 자극성과 SPF 측정)

  • Kim, In-Young;Kang, Sam-Woo
    • Analytical Science and Technology
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    • v.11 no.2
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    • pp.79-87
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    • 1998
  • Consumers have recently preferred to purchase extensive UV intercepting products, which are waterproof and free from side effects on skin. During the testing of cytotoxicity (in-vitro) in neutral red (NR) method, cell survival ratio of UV-B interceptors decreased to just above 0.08 w/v%, and it was observed that the UV-A interceptors the ratio also decreased to just above 0.06 w/v%. In addition patch-tests of inorganic UV interceptors resulted in no skin irritation even below 10.0 and 11.25. In absorption curves, UV-B was most suitable for octyl methoxycinnamate (OMC) and UV-A for butyl methoxy dibenzoylmethane (BMDM). For this reason, $Nylonpoly^{TM}$ UVA/UVB the material of OMC and BMDM coated with Nylon & polyethylene, was used as the organic UV interceptor. Zinc oxide (ZnO) and titanium dioxide ($TiO_2$) was used as inorganic UV interceptors. The appropriate mixture ratio of ZnO and $TiO_2$ was 6 to 4:6% of ZnO, 4% of $TiO_2$ and 5% of $Nylonpoly^{TM}$ UVA/UVB were all combined and added to our sunscreen cream. The SPF value of in-vitro was 38.9. In practical application, each sun protection factor (SPF) duration of oil-in-water (O/W) emulsion and water-in-silicone (W/S) emulsion containing sunscreen cream of the same content showed that W/S type of sunscreen cream was 5 times as durable as the other. Therefore, this product is fit for use in swimming, climbing or skiing. This research is to minimize skin trouble caused by UV interceptors and to make one with proper softness, skin safety and UV intercepting efficiency.

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