• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.822-828
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• 2005

The photocatalytic degradation of methyl parathion was carried out using a circulating $TiO_2$/solar system. Under the photocatalytic condition, parathion was more effectively degraded than by the photolysis or $TiO_2$ only condition. The parathion degradation followed pseudo first-order kinetics. With photocatalysis, 10 mg/L parathion was completely degraded within 90 min with a TOC decrease exceeding 63% after 150 min. The nitrogen from parathion was recovered mainly as ${NO_2}^-$, ${NO_3}^-$, and ${NH_4}^+$, 80% of sulfur as ${SO_4}^{2-}$, and less than 5% of phosphorus as ${PO_4}^{3-}$ during photocatalysis. The organic intermediates 4-nitrophenol and paraoxon were also identified, and these were further degraded. Two different bioassays using V. fischeri and D. magna were employed to measure the toxicity reduction in the solutions treated by both photocatalysis and photolysis. Relative toxicity was reduced almost completely after 150 min in both organisms under the photocatalysis, whereas in photolysis, 76 and 57% reduction was achieved for V. fischeri and D. magna, respectively. The acute toxicity reduction pattern corresponded with the decrease in parathion and TOC concentrations.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.367-374
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• 1975

Glycine residue in N-X-glycylphenylalanine methyl ester(X = trifluoroacetyl or acetyl) was converted into aspartic acid derivative by a photoalkylation reaction. The reaction was induced with 350 nm lamp using a combination of diacetyl/di-t-butyl peroxide (DBP) as the photoinitiator, and acetic anhydride as the alkylating agent. In the thermal reaction with DBP and acetic anhydride, the same alkylation reaction of the dipeptide was observed. From this thermal alkylation reaction the photoalkylation reaction is also thought to undergo via free radical mechanism.

• KSBB Journal
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• v.18 no.4
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• pp.340-345
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• 2003

Feasibility of large-scale photobioreactors for biological CO$_2$ fixation was investigated using Chlorella sp. HA-1. Generally, as the volume of photobioreactor increased, the CO$_2$ fixation rate decreased because of a lower illumination efficiency in large-scale than in small-scale photobioreactors. Though controlling the arrangement and the number of light source, the maximum CO$_2$ fixation rates that could be achieved were 530 and 357 gCO$_2$/㎡day for 40 L and 188 L photobioreactor, respectively, which was higher than the CO$_2$ fixation rate of lab-scale photobioreactor.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.179-183
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• 2011

In this study, photochemical effects (OH radical formation) in the photoreactor was investigated to analyze UV-C intensity distribution. In addition, The influence radius of the UV-C lamp was measured at various dose of $TiO_2$ (Degussa P-25). The photoreactor used in this study was bath type reactor which is made by acrylic and the UV-C lamp (SANKYO DENKI, wavelength : 254 nm, Diameter : 2.2 cm, Length : 18.5 cm) was used as photo source. The maximum electric power consumption of the UV lamp was 10.5 W. The OH radical formation by UV-C was measured by KI dosimetry methods. From the results, the effective OH radical formation was occurred under the following condition. The reasonable distance of UV-C lamp is within 13 cm and the intensity of UV-C lamp should be more than 0.367 mW/$cm^2$. Moreover, the concentration of catalyst affects on the influence radius of the UV lamp.

• Analytical Science and Technology
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• v.15 no.4
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• pp.341-345
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• 2002

The extent of UV-curing photo-polymerization reaction was monitored by near-IR spectroscopic method. Acrylates containing quaternary ammonium salts and Darocur 1173 were used as reactive monomer and a photo initiator, respectively. The extent of photo-polymerization reaction was obtained from the conversion ratio of acrylate double bond calculated from the intensities of measured bands at 1615 nm and at 2105 nm. Near-IR spectroscopic methods can be an useful tool for the monitoring of the progress of photo-polymerization.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.66-72
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• 2008

The photocatalytic degradation of a textile diazo dye in aqueous solution has been investigated under Solar and UV-A light. The effect of various parameters such as concentration of dye, amount of catalyst and pH on the degradation of dye has been studied. Addition of hydrogen peroxide, ammonium persulphate and isopropanol strongly influences the degradation rate. Kinetic analysis of photodegradation reveals that the degradation follows approximately pseudo first order kinetics according to the Langmuir-Hinshelwood model. Carbon dioxide, nitrate and sulphate ions have been identified as mineralisation products. The photocatalyst ZnO was found to be more efficient in UV-A light than in Solar light.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.517-523
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• 2008

The degradation mechanism of Triclosan(TCS), which is a potent broad-spectrum antimicrobial agent and has been considered as an emerging pollutant, was investigated in the Fenton and the hybrid reaction with Fe$^{2+}$ and UV-C. The results show that the Fe$^{2+}$ is oxidized to 30% by $H_2O_2$, 28% by UV-C, and 15% by UV-A for 10 min. The degradation rate of TCS for beginning time(10 min) was higher in UV-C only reaction than that in hybrid reaction, which of the order was inverted according to the lapse of reaction time. The effect of methanol was the greatest in Fenton reaction, in which the degradation rate of TCS decreased from 90% to 5% by the addition of methanol. Chloride, ionic intermediate, was produced to 77% for 150 min of hybrid reaction(Fe$^{2+}$ + UV-C), which was the greatest. In case with methanol, the generation rate of chloride for 15 min was ignorable in all reactions($\leq$2%) but the hybrid reaction with Fe$^{2+}$ and UV-C(12%). Additionally, the removal rate of TOC in each reaction was estimated as the followed orders; Fe$^{2+}$ + UV-C > Fe$^{2+}$ + $H_2O_2$ > Fe$^{2+}$ + UV-A > UV-C > UV-A. However, the Fenton reaction was almost stopped after 90 min because the reaction between Fe$^{2+}$ and $H_2O_2$ cannot be kept on without adding the oxidant. The phenomena was not observed in the hybrid reaction. In view of generating chloride, the reductive degradation of TCS may be in the hybrid reaction with Fe$^{2+}$ and UV-C, which is favorable to mineralize halogenated organic compounds such as TCS. Consequently, the hybrid process with Fe$^{2+}$ and UV-C may be considered as the alternative treatment method for TCS.

• Journal of the korean Society of Automotive Engineers
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• v.6 no.2
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• pp.55-63
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• 1984

Berglund-Liu 진동방식 단분산 분체입자 발생기(Berglund-Liu vibrating orifice monodisperse aerosol generator)에 의하여 제작한 단분산 광흡수성 표준분체입자를 사용하여 레이저 산란광 분체입도 측정기 (Knollenberg active scattering aerosol spectrometer)의 반응특성을 조사하 였다. 실험결과, 기기의 반응특성은 Mie 산란이론에 의하여 계산한 이론치와 매우 잘 일치하며 특히 광흡수성 분체입자는 광통과성 분체입자가 다의적인 특성을 나타내는 것에 반하여 거의 단조증가하는 일의적인 특성을 가지고 있으며 광흡수성 분체입자의 반응특성이 제작자의 교정 치에 가까운 결과를 나타내었다.

• Analytical Science and Technology
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• v.17 no.3
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• pp.225-229
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• 2004

The effect of the silicon acrylate as a reactive additive on the UV-curing photopolymerization reaction was studied by micro raman technique. For the study, acrylate systems and Darocur 1173 were used as oligomer and monomers, and a photo initiator, respectively. The content of silicon acrylate was within the range of 0-3 wt%. The extent of photo-polymerization reaction as a function of depth from the air interface was obtained from the conversion ratio of acrylate double bond calculated from the intensities of measured bands at $1410cm^{-1}$ and at $1635cm^{-1}$. Micro raman spectroscopic technique can be an useful tool for the investigation of the factors, which can affect the reaction progress, such as oxygen inhibition, composition of the formulations, depth, etc.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.441-448
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• 1998

Defined spatial localization of biomolecules on the polymer surface Is potentially powerful method to generate biocompatible surface. Photolithography and photochemistry can be used to immobilize peptides only al a given region of the surface. In this study, peptide RGDS, one of the endothelial cells recognition sites of fibronectin, was covalently immobilized on the polystyrene coated surface with micropattern. It was performed by photochemical reactivity of a synthesized N-hydroxysuccinimidyl phenyl azide. The micropatterning was confirmed by staining with fluorescent dye, aminoacetamido fluorescein. Endothelial cell adhesion was observed only on the RGDS immobilized areas.