• Journal of Environmental Science International
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• v.13 no.1
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• pp.41-45
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• 2004

In this study, The decomposition of gas-phase Benzene and Toluene, Xylene in air streams by direct UV Photolysis, UV/TiO$_2$ and UV/TiO$_2$/A.C process was studied. The experiments were carried out under various UV light intensities and initial concentrations of B.T.X to investigate and compare the removal efficiency of the pollutant. B.T.X was determined by GC-FID of gas samples taken from the a glass sampling bulb which was located at reactor inlet and outlet by gas-tight syringe. From this study, the results indicate that UV/TiO$_2$/A.C system (photooxidation-photocatalytic oxidation-adsorption process) is ideal for treatment of B.T.X from the small workplace. Although the results needs more verifications, the methodology seems to be reasonable and can be applied for various workplace (laundry, gas station et al.).

• Journal of the Semiconductor & Display Technology
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• v.6 no.1 s.18
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• pp.65-69
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• 2007

A design of experiments was applied in order to investigate the effect of processing variables in UV irradiation on the electrical/optical properties in indium-zinc oxide thin films, The processing variables, equivalently input variables are listed as UV irradiation time, oxygen flow rate, and chamber pressure. The statistical significance of Ultra Violet (UV) treatment was confirmed using a paired-t test. The full factorial $2^3$ design was employed to determine significant main and interaction effects in UV irradiation process. The chamber pressure and the interaction between UV irradiation time and $O_2$ flow rate were found to be statistically significant at the significance level of 0.1. Furthermore, the optimized approach was proposed in achieving the improved conductivity after UV irradiation.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.521-533
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• 2012

Interest in application of ultraviolet light technology for primary disinfection that used for the treatment of water for consumption and wastewater has increased significantly in recent years. Analysis of these systems has been carried out using Computational Fluid Dynamics (CFD) procedure. It offers advantages over other techniques in specific circumstances. CFD has emerged as a powerful tool to aid design of a UV reactor by providing the UV dose delivered by the proposed reactor design and allowing engineers to evaluate alternative designs in much less time and at a reasonable cost. In this study, five different configurations of the apparatus depending on the location of the exit are evaluated in terms of maximum dose, minimum dose, flow patterns, particle tracks and transient dose. The configuration 3 results have higher minimum UV dose value and uniform particle distribution of the UV dose on the outlet than other's.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.9
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• pp.1463-1471
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• 2009

Silver ions or silver nanoparticles have multi-functional properties. The cotton fabrics for providing multi-functional properties were treated with a nanosilver powder, UV-absorbers, and dimethyloldi-hydroxyethyleneurea (DMDHEU) alone and mixed solution. The physical properties, UV protection, antibacterial, and deodorizing properties of treated cotton fabrics were evaluated. The results were as a follows. The UV protection of cotton fabrics were increased by the application of a nanosilver and Uv-absorbers mixture. The UV protection of treated fabrics were improved by nanosilver/DMDHEU/UV-absorbers mixed solution. The wrinkle recovery properties of fabrics treated with DMDHEU and nanosilver improved. The stiffness of fabrics are decreased by a nanosilver/DMDHEU/UV-absorbers mixed solution. The antibacterial properties of the fabrics treated with nanosilver/DMDHEU/UV-absorbers mixed solution is 99.99%. The functional properties of cotton fabrics are shown to be better with aanosilver/DMDHEU/UV-absorbers mixed than treated with nanosilver alone.

• Journal of Mushroom
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• v.13 no.3
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• pp.256-261
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• 2015

This study was conducted to reduce contamination ratio of oyster mushroom bottle cultivation. The optimal conditions of substrate sterilization for reducing of contamination ratio were at $121^{\circ}C$ for 90 min. In addition, UV-C irradiation is good for lower contamination ratio to continue over 6 hours at cooling and inoculation room after sterilization. The contamination ratio and density of microorganisms of substrate were showed 0% after sterilization at $121^{\circ}C$ for 90 min. Trichoderma sp., main pathogen of mushrooms, was detected from substrate after sterilized during 2 or 4 hours at $101^{\circ}C$ and $105^{\circ}C$, respectively. The amount of electricity used was the lowest at $121^{\circ}C$ for 90 min than that of other sterilization conditions. The UV-C irradiation treatment was used UV-C lamp(40 watts) in the inoculation room($56m^3$). The density of bacteria did not detected after UV-C irradiation for 6 hours. And the death ratio of bacteria and Trichoderma sp. was 99.9% after UV-C irradiation for 6 hours. However, in the same UV-C irradiation time, the death ration of Cladosporium sp. was 90.9%. Therefore, the death ratio of fungi was lower than that of bacteria at the same UV-C irradiation treatment.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.318-325
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• 2017

Wastewater including ethanolamine used in the second generation of nuclear power plants is filtered out in the ion exchange resin of the condensate polishing plant. In the regeneration process of ion exchange resin, a strong acidic wastewater containing ethanolamine and a lager amount of ionic substances are released. In this study, the process involving UV oxidation part with or without absorbents was developed for treating wastewater released from the ionic exchange resin. The effect of adsorbents on the wastewater treatment was investigated by using UV oxidation system developed by us. As a result, the COD removal efficiency of UV/GAC process with the granular activated carbon (GAC) as an adsorbent was 71.3% at pH 12.8. The removal efficiency was 21.8% higher than that of the wastewater treated using UV oxidation process without any adsorbents at the same condition. The removal of T-N was 88.6% at pH 12.8 when using UV oxidation with the GAC absorbent, which was 18.0% higher than that of using the UV oxidation process without any absorbents. It is thought that ethanolamine adsorbed on the absorbent improved the efficiency of UV oxidation process. Therefore, the UV/GAC adsorption oxidation process can be more effective in treating wastewater containing ethanolamine than that of using the process without any absorbents.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.5
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• pp.53-59
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• 2008

This study was carried out to investigate the effect of photocatalysis using $TiO_2$ and UV applied for the COD reduction of wastewater in linerboard mill. Trials were done to obtain the optimum addition amounts of $TiO_2$ and $H_2O_2$ to the wastewater and find an appropriate pH condition for photocatalysis on $TiO_2$ for degrading COD. The photocatalytic reaction was applied to the wastewater collected after secondary activated sludge treatment in WWTP of linerboard mill. The optimum application of photocatalysis reaction was obtained under the addition conditions of 2 g/L of $TiO_2$ and 200 mg/L of $H_2O_2$ at pH 3.0, respectively. The removal efficiency of $SCOD_{Cr}$ by photocatalytic treatment was 86.4 % and higher than Fenton treatment in which removal efficiency was 67.4 %. It was concluded that the photocatalytic process using $TiO_2$ and UV could be applied to the wastewater treatment in linerboard mill and also to the dramatic drop-off in NBDCOD load from wastewater of tertiary treatment in WWTP.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.2
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• pp.209-216
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• 2019

Ultraviolet rays (UV) cause photoaging by inducing skin photodamages such as erythema and sunburn. Silymarin is a mixture of antioxidant polyphenols extracted from Silybum marianum fruit (S. m), which is known as milk thistle. It is known to protect skin tissues from UV treatment and antioxidant effects. In this study, we aimed to identify the photoprotective effects of S. m extract, which has silymarin in the epidermis layer of the skin. We found that the extract can function as a UV filter, so it can reduce DNA damage by UV treatment. Especially, we found that, in the stratum corneum, the extract can suppress the protein carbonylarion and DNA damages caused by suberythemal dose of UV treatment which does not induce erythema in the skin. UV treatment also increased protein carbonylation levels in the stratum corneum by oxidation, but it was prevented by applying the extract. The extract can absorb UV with minimal phototoxicity. Together, our study suggests that S. m extract can be used as a photo-protective ingredient to avoid photoaging of the skin.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.459-469
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• 2019

The ozonation of sulfamethoxazole (SMX) was performed at 20℃ using a pilot scale countercurrent bubble column reactor. Ozonation systems were combined with UV irradiation and TiO₂ addition. As the oxidation reaction proceeded in each treatment system, the pH of the sample decreased and in the O₃/UV/TiO₂ system, the pH change was the largest from 4.54 to 2.02. Under these experimental conditions, the scavenger impact of carbonate is negligible. The highest COD and TOC removal rate was observed in the O₃/UV/TiO₂ system due to the UV irradiation and the photocatalytic effect of TiO₂. Also, the highest mineralization ratio(ε) value is 0.2 in the O₃/UV/TiO₂ system, which means theoxidation capacity of the systems. The highest SMX degradation rate constants calculated by COD and TOC values (COD and TOC) were 2.15 × 10^-4 sec^-1 and 1.00 × 10^-4 sec^-1 in the O₃/UV/TiO₂ system, respectively. The activation energy (E_a) of ozone treatment follows the Arrhenius law. It was calculated based on _COD and _TOC. Each activation energy decreased in order of single O₃> O₃/TiO₂> O₃/UV > O₃/UV/TiO₂ system. The result showed that ΔH^≠ is more effective than ΔS^≠ in each SMX ozontaionsystem, that is characteristic of the common oxidation reaction.

• Environmental Engineering Research
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• v.12 no.2
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• pp.64-71
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• 2007

The necessity of disinfecting playground soil is an important issue, because pathogenic protozoa, bacteria, and parasite eggs remain viable for several months and can infect children. UV irradiation has been used to decontaminate water but its effectiveness on soil is unclear. We determined the efficacy of UV radiation for inactivation of an indicator bacteria, E. coli (strain ATCC 8739), on playground soil. While 99% inactivation of E. coli in the soil was readily achieved by UV radiation within 55 min at $0.4\;mW\;cm^{-2}$, complete inactivation was not achieved, even after prolonged treatment at $4\;mW\;cm^{-2}$. This was attributed to the irregular surface of the soil. A small number of E. coli escaped the UV radiation because they were situated in indentations or under small particles on the soil surface. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) confirmed that the surface characteristics of the soil is the major limiting factor in the inactivation of E. coli by UV radiation. Thus UV treatment may not be adequate for disinfecting some soils and should be carefully evaluated before being used on playground soils.