• Transactions on Electrical and Electronic Materials
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• 제17권4호
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• pp.204-207
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• 2016

Experimental study of UV-irradiated O₂/H₂ gas phase cleaning for PMMA (Polymethylmethacrylate) removal is carried out in a load-locked reactor equipped with a UV lamp and PBN heater. UV enhanced O₂/H₂ gas phase cleaning removes polymethylmethacrylate (PMMA) better at lower process pressure with higher content of H₂. O₂ gas compete for UV (184.9 nm) absorption with PMMA producing O₃, O(¹D) and lower dissociation of PMMA. In our experimental conditions, etching reaction of PMMA at the substrate temperature between 75℃ and 125℃ had activation energy of about 5.86 kcal/mol indicating etching was controlled by surface reaction. Above the 180℃, PMMA removal was governed by a supply of reaction gas rather than by substrate temperature.

• 상하수도학회지
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• 제24권1호
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• pp.109-117
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• 2010

In the present study, the degradation characteristics of Lindane by Advanced Oxidation Processes(UV/$H_2O_2$, Photo-Fenton process) were studied. The degradation efficiency of Lindane in aqueous solution was investigated at various initial pH values, Fenton's reagent concentrations and initial concentrations of Lindane. GC-ECD was used to analyze lindane. Lindane has not been degraded without application of AOPs over two hours. But, approximately 5% of lindane was degraded with UV or $H_2O_2$ alone. Lindane with UV/$H_2O_2$ process showed approximately 7% higher removal efficiency than $H_2O_2$ process. In the UV/$H_2O_2$ process, the pH values did not affect the removal efficiency. The optimal mole ratio of $H_2O_2/Fe^{2+}$ for lindane degradation is about 1.0 in Photo-Fenton process. Also, the experimental results showed that lindane removal efficiency increased with the decrease of initial concentration of lindane. Under the same conditions, the order lindane of removal efficiency is as following : Photo-Fenton process > UV/$H_2O_2$ process > $H_2O_2$ process. In addition, intermediate products were identified by GC-MS techniques. Than PCCH(Pentachlorocyclohexene) was identified as a reaction intermediate of the Photo-Fenton process.

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.985-993
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• 2006

An experiment to find out the removal mechanism of PEG(polyethyleneglycol) by using UV-enhanced $O_2$ GPC (gas phase cleaning) at low substrate temperature below $200^{\circ}C$ was executed under various process conditions, such as substrate temperature, UV exposure, and $O_2$ gas. The possibility of using $UV/O_2$ GPC as a low-temperature in-situ cleaning tool for organic removal was confirmed by the removal of a PEG film with a thickness of about 200 nm within 150 sec at a substrate temperature of $200^{\circ}C$. Synergistic effects by combining photo-dissociation and photo oxidation can only remove the entire PEG film without residues within experimental splits. In $UV/O_2$ GPC with substrate temperatures higher than the glass transition temperature, the substantial increase in the PEG removal rate can be explained by surface-wave formation. The photo-dissociation of PEG film by UV exposure results in the formation of end aldehyde by dissociation of back-bone chain and direct decomposition of light molecules. The role of oxygen is forming peroxide radicals and/or terminating the dis-proportionation reaction by forming peroxide.

• 한국물환경학회지
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• 제21권3호
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• pp.267-273
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• 2005

Dye wastewater generally contains strong color and non-biodegradable materials. Therefore, the conventional wastewater treatment plant can hardly meet the regulation of wastewater effluent water. In this study, a pilot plant of the conventional process followed by advanced oxidation process (AOP), was set up to treat the dying wastewater. The treatment efficiencies on the various candidate processes, such as ozone alone, UV alone, ozone/UV, $ozone/H_2O_2$, $H_2O_2/UV$ and $ozone/UV/H_2O_2$, were investigated in the various ozone and $H_2O_2$ doses. As the results, the $ozone/H_2O_2$ process, among the tested processes, showed the highest efficiency for removing color and $COD_{Cr}$. For color removal, the ozone alone process was enough without combining UV or $H_2O_2$. No significantly enhanced efficiency for removing color and $COD_{Cr}$ by UV irradiation was observed because of the very low transmittance of UV light in dye wastewater.

• 공업화학
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• 제9권1호
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• pp.28-32
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• 1998

두 종류의 유기인계 살충제인 디클로로보스와 클로로피리포스를 UV조사, UV 조사와 $TiO_2$분말 그리고 UV조사와 sea sand를 저압수은 램프를 이용하여 분해실험을 하였다. 이 화합물의 확인은 가스크로마토그래프, 총유기탄소 그리고 이온크로마토그래프를 사용하였다. 두 물질 모두, UV조사와 sea sand가 UV 조사와 UV조사와 $TiO_2$분말보다 분해가 더 잘 되었다. 반응 최종생성물은 디클로르보스에서는 $Cl^-$, 클로로피리포스에서는 $Cl^-$ $SO_4{^{2-}}$등이 생성되었다.

• 한국식품위생안전성학회지
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• 제33권6호
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• pp.495-499
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• 2018

후춧가루에 존재하는 식중독 균을 저감화시키기 위한 방법으로 UV-C와 mild heat를 병합 처리 가능성을 타진하였다. Escherichia coli O157:H7 (ATCC 35150)와 Salmonella Typhimurium (ATCC 19585)를 후춧가루에 각각 $10^6$, $10^7CFU/g$ 수준으로 인위접종하여 $2.32W/cm^2$의 UV-C와 $60^{\circ}C$의 mild heat을 10분에서 70분 동안 처리하였다. 그 후 미생물 분석 및 후춧가루의 품질변화를 측정하였다. UV-C를 단독으로 70분 동안 처리했을 때 E. coli O157:H7과 S. Typhimurium는 각각 1.89, 2.24 log CFU/g 수준으로 감소하였지만, UV-C와 mild heat을 70분 동안 병합처리 했을 때는 각각 2.46, 5.70 log CFU/g으로 감소하였다. E. coli O157:H7 보다는 S. Typhimurium의 저감효과가 더 컸다. 색도는 모든 처리구에서 유의적인 차이가 없는 것으로 나타났다. 따라서 UV-C와 mild heat 병합처리는 후춧가루에 존재하는 식중독 균을 사멸시키는 데 효과적이기 때문에 산업적인 살균처리 기술로 활용될 수 있을 것으로 판단되었다.

• 환경위생공학
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• 제15권4호
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• pp.27-27
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• 2000

In order to treat the dyeing wastewater, the UV/TiO₂/H₂O₂ system was investigated, and proper pretreatment methods were examined to reduce the load on the system considering economical and technical efficiency. The results of this study were as follows: 1.UV/TiO₂/H₂O₂ system with pretreatment process was adopted, the result of Chemical coagulation and pH control units was pH 11→ coagulation → pH 4 and the optimum dosage of FeCl₃ was 600㎎/ℓ 2. Proper dosage of TiO₂in the UV/TiO₂/H₂O₂ system with pretreatment process was 2g/ℓ and H₂O₂ was 1000㎎/ℓ, UV contact time was 20min to get below 200㎎/ℓ of $COD_{Cr}$

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1895-1899
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• 2012

$SiO_2$-coated $TiO_2$ composite materials with enhanced photocatalytic activity under UV light was prepared by a simple catalytic hydrolysis method. XRD, TEM, UV-vis spectroscopy, Photoluminescence, FT-IR and XP spectra were used to characterize the prepared samples. The obvious shell-core structure was shown for obtained $SiO_2$@$TiO_2$ sample. The average thickness of the $SiO_2$ coating layer was 2-3 nm. The interaction between $SiO_2$ and $TiO_2$ restrained the recombination of excited electrons and holes. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under UV light. The photocatalytic activity of $SiO_2$@$TiO_2$ was much higher than that of P25 and mechanical mixing sample $SiO_2/TiO_2$. The possible mechanism for the photocatalysis was proposed.

• 대한환경공학회지
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• 제27권10호
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• pp.1129-1135
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• 2005

한강에서 추출한 휴믹물질의 산화를 위해 회전 반응기를 도입하였다. $TiO_2$ 광촉매의 혼합을 위해 사용되는 공기는 UV 램프와 광촉매 사이에서 UV 조사를 방해할 수 있으므로, 더 나은 UV 조사율을 위해 반응기 내부에 배플이 설치된 회전 반응기를 고안하였다. FT-IR, $^{13}C$-NMR의 분석 결과, 한강 휴믹물질은 다른 상용화된 휴믹물질과는 다른 특성을 보여주었다. XAD-7HP 수지로 분리된 한강 휴믹물질을, 반응 후 광촉매의 분리 및 회수문제를 해결하기 위해, $TiO_2$를 hollow bead에 고정화한 광촉매와 UV-A, UV-C 램프를 사용하여 광촉매산화시켰다. 초기 휴믹물질의 TOC 농도가 5 mg/L일 때, 초기 pH 3, $TiO_2$ 주입률 2.0 g/L을 최적 조건으로 결정하였다. 또한 UV-C와 UV-A 램프의 비교실험을 수행한 결과, 비슷한 TOC 제거율을 보였다. 하지만, 분자량 분포 실험 결과, UV-A 램프보다 UV-C 램프로 광촉매산화시킨 것이 상대적으로 저분자량 부분이 증가하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.256-256
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• 2011

We have deposited Al2O3 thin films on Si substrates at room temperature by UV-enhanced atomic layer deposition using trimethylaluminum (TMA) and H2O as precursors with UV light. The atomic layer deposition relies on alternate pulsing of the precursor gases onto the substrate surface and subsequent chemisorption of the precursors. In many cases, the surface reactions of the atomic layer deposition are not completed at low temperature. In this experiment, the surface reactions were found to be self-limiting and complementary enough to yield uniform Al2O3 thin films by using UV irradiation at room temperature. The UV light was very effective to obtain the high quality Al2O3 thin films with defectless.