• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.574-583
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• 2021

Waste air containing ethanol (100 ppmv) and hydrogen sulfide (10 ppmv) was continuously treated by waste air-treating system composed of two annular photocatalytic reactors (effective volume: 1.5 L) packed with porous SiO₂ media carrying TiO₂-anatase photocatalyst, one of which was alternately operated for 32 d/run while the other was regenerated by 100 ℃ hot air with 15 W UV(-A)-light on. As its elimination-behavior of ethanol, the removal efficiencies of ethanol at 1^st, 2^nd and 3^rd operation of the photocatalytic reactor system(A), turned out to be ca. 60, 55 and 54%, respectively, at their steady state condition. Unlike the elimination-behavior of ethanol, its hydrogen sulfide-elimination behavior showed repeated decrease of hydrogen sulfide removal efficiency by its resultant arrival at a lower level of steady state condition. Nevertheless, the removal efficiencies of hydrogen sulfide at 1^st, 2^nd and 3^rd operation of the photocatalytic reactor system, turned out to be ca. 80, 75 and 73%, respectively, at their final steady state condition, higher by ca. 20, 20 and 19% than those of ethanol, respectively. Therefore, assuming that adsorption on porous SiO₂-photocatalyst carrier was regarded to belong to a reversible deactivation and that decreased % of removal efficiency due to the reversible deactivation of photocatalyst including the adsorption was independent of the number of its use upon regeneration, the increments of the decreased % of removal efficiency of ethanol and hydrogen sulfide, due to an irreversible deactivation of photocatalyst, for the 3^rd use of regenerated photocatalyst, compared with the 2^nd use of regenerated photocatalyst, were ca. 1 and 2%, respectively, which was insignificant or the less than those of ca. 5 and 5%, respectively, for the 2^nd use of regenerated photocatalyst compared with the 1^st use of virgin photocatalyst. This trend of the photocatalytic reactor system was observed to be similar to that of the other alternately-operating photocatalytic reactor system.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.163-169
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• 2005

Photocatalytic oxidation of Cu(II)-EDTA has been studied using solar/$TiO_2$ photocatalysis as an energy source. Photocatalysis efficiency on the treatment of Cu(II)-EDTA was investigated using different types of solar collectors as well as by variation of the angles of solar collector solar light intensities, flow rates, and areas of solar collector. effect of $H_2O_2$ and types of $TiO_2$ catalyst on the treatment of Cu(II)-EDTA was also investigated. Removal of Cu(II) and DOC was favorable with a hemispherical collector than with a flat collector Removal of Cu(II) and DOC increased with increasing angles of solar collector up to $38^{\circ}$. Slurry type $TiO_2$ showed four-times higher removal efficiency than immobilized type $TiO_2$. Removal of both Cu(II) and DOC at a clear sky of solar light intensity ranging from 0.372 to $2.265\;mW/cm^2$ was greater than removal at a cloudy day of solar light intensity ranging from 0.038 to $1.129\;mW/cm^2$. From the result of this research that the removal efficiency of Cu(II) and DOC increased as the solar light intensity increased, it can be inferred that quantum yield in the destruction of Cu(II)-EDTA may directly related with the solar light intensity. Removal of Cu(II) increased as increasing the area of solar collector and was similar at lower flow rates white removal of Cu(II) was interfered at higher flow rates. When immobilized $TiO_2$ was used, removal efficiency of Cu(II) increased in the presence of $H_2O_2$ while negligible effect was found in the use of $TiO_2$ slurry.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.65-71
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• 2016

In this study, Antimony Tin Oxide (ATO) ion storage layer and $TiO_2$ working electrode were fabricated using Nano Particle Deposition System. NPDS is the cutting-edge technology among the dry deposition methods. Accelerated particles are deposited on the substrate through the nozzle using NPDS. The thicknesses for coated layers were measured and layer's morphology was acquired using SEM. The fabricated electrochromic cell's transmittance was measured using UV-Visible spectrometer and power source at 630 nm. As a result, the integrated electrochromic/DSSC hybrid system was successfully fabricated as an energy harvesting system. The fabricated electrochromic cell was self-operated using DSSC as a power source. In conclusion, the electrochromic cell was operated for 500 cycles, with 49% of maximum transmittance change. Also the photovoltaic efficiency for DSSC was measured to be 2.55% while the electrochromic cell on the integrated system had resulted in 26% of maximum transmittance change.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.463-467
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• 2003

Fundamental experiments were carried out about color removal efficiency of dyeing wastewater using a $bioreactor-TiO_2/UV$ reactor system. Color removal efficiencies of the Reactive Black 5 in the system were found to bo more than 80% in changes of dilution rate 0.04 to $0.08hr^{-1}$. In this research, a new color removal system of dying wastewater will be proposed after more investigation of decolorization efficiencies about different dyes and condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.197-197
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• 2010

본 연구에서는 RF/DC dual 마그네트론 스퍼터 시스템을 이용하여 Glass 기판 상에 유기태양전지용 Nb-doped $TiO_2$ (NTO)/Ag/NTO 다층 투명전극을 성막하고 이 다층 투명전극을 $200^{\circ}C{\sim}700^{\circ}C$ 온도 범위에서 급속 열처리 (Rapid Thermal Annealing ; RTA)를 통하여 전기적, 광학적, 구조적 및 표면의 특성 변화를 연구하였다. Hall effect measurement, UV-Vis spectrometer, FESEM 분석을 통하여 다층투명전극의 전기적, 광학적, 표면분석을 하였고 Synchrotron 분석을 통하여 온도에 따른 구조변화를 분석하였다. 상온에서 성막된 다층투명전극은 30nm 두께의 NTO 박막 사이에 얇은 9nm의 얇은 Ag 층을 삽입한 구조로써 10ohm/square 이하의 매우 낮은 면저항과 ${\sim}10^{-5}\;ohm-cm$ 의 비저항, Anti-reflection 효과에 의해 85% 이상의 높은 광투과성을 나타내었다. RTA 온도가 증가함에 따라 전기적, 광학적 특성은 약간 향상되었고 비정질 구조를 유지함을 알 수 있었다. 그러나 높은 온도범위에서는 비정질 구조에서 Anatase 상으로 결정구조가 변화함을 알 수 있었고 전기적, 광학적 특성이 감소됨을 알 수 있었다. NTO/Ag/NTO 다층 투명전극을 유기태양전의 Anode로 적용하여 특성을 비교한 결과 RTA 온도가 증가함에 따라 유기태양전지의 효율 또한 증가하였고 최적화된 온도 조건에서 2.49% 의 높은 효율을 얻을 수 있었다. 이를 통해 우수한 특성을 나타내는 NTO/Ag/NTO 다층투명전극이 기존의 디스플레이 및 태양전지 등의 투명전극 재료로 주로 사용되어 온 ITO (Indium Tin Oxide) 를 대체 할 수 있는 재료로써의 가능성을 제시하였다.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.837-845
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• 2017

A recirculating integrated system composed of a fluidized biofilter filled with waste-tire crumb media fixed with return sludge from wastewater treatment facility of D dyeing industrial center, and a UV/photocatalytic reactor packed with calcined $TiO_2$ coated-glass beads as photocatalyst-support, was constructed and was run to treat authentic textile-dyeing wastewater from D-dyeing industrial center, which was mixed with an alkaline polyester-weight-reducing wastewater and a wastewater from sizing process. As a result, its total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were ca. 81% and 55%, respectively. The synergy effect of the recirculating integrated system to enhance total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were evaluated at most ca. 7% and 3%, respectively. The fluidized biofilter and the UV/photocatalytic reactor were responsible for ca. 94% and 6% of the total $COD_{cr}$ removal efficiency, respectively, and were also responsible for ca. 86% and 14% of the total color-removal efficiency, respectively. Thus, the degree of the UV/photocatalytic reactor-unit process's contribution to RE(tot) of color, was about 2.4 times of that to RE(tot) of $COD_{cr}$. Therefore, the UV/photocatalytic reactor facilitated the more effective elimination of colors by breaking down the chemical bonds oriented from colors of dyes such as azo-bond, than $COD_{cr}$. In addition, the effect of the removal efficiency of each unit process(i.e., the fluidized biofilter or the UV/photocatalytic reactor) of the recirculating integrated system on RE(tot) of $COD_{cr}$ and colors, was analysed by establishing its model equation with an analytic correlation.

• Transactions of the Society of Information Storage Systems
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• v.3 no.1
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• pp.17-22
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• 2007

[ $TiO_2$ ] nanoparticles are added into UV curable resin to increase the refractive index of the cover-layer which is laminated on the media for cover-layer incident NFR. High refractive index is required for the cover-layer operating for the solid immersion lens optics with high effective numerical aperture. The eyepattern could be achieved from the cover-layer coated 20 GB ROM disc in which the refractive index of the cover-layer was 1.75, but the gap servo was unstable due to the rough surface of the cover-layer. Even though the light loss due to the nanoparticles is not serious, the rough microstructure is developed by adding the nanoparticles in the organic binder material. To achieve smooth surface for the stable gap servo, some special techniques should be added, for example the solubility of the nanoparticles should be enhanced by the optimization of the surface of the nanoparticles.

• Journal of Power System Engineering
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• v.11 no.2
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• pp.64-71
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• 2007

The main purpose of this study is to analyze the characteristics of toluene removal by plasma, photocatalyst, and plasma/photocatalyst system with the major parameters such as flow rate, inlet toluene concentration and applied voltage, etc., experimentally. In the combined plasma/photocatalyst process, rates of toluene conversion are represented as 99% at flow rate 250, 500 mL/min while, below 97% at flow rate 1000 mL/min due to the low residence time(reaction time) at the same applied voltage 4173 voltage and toluene inlet concentration 50 ppm. The intermediate products are detected by GC/MS analysis showing the small amounts of benzoic acid, benzyl alcohol and residual ozone concentration $0.04{\sim}0.05$ ppm generated by plasma process in the present system.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2119_2120
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• 2009

전압을 인가하였을 때 전계방향에 의해 가역적으로 색이 변화하는 현상을 전기변색(electrochromism)이라고 한다. 이러한 전기채색현상을 보이는 물질을 전기채색물질(electrochromism materials)이라고 하며, 전기채색 물질에 의한 소자를 전기채색소자(electrochromism device : ECD)라고 한다. 전기채색현상은 투과율(transmittance), 반사율(reflectance)의 가역적이며 가시적인 변화이고, 전기화학적인 산화환원 반응과 관련이 있다. 따라서 본 연구에서는 Titanate nanotube(TNT)를 제조하고 전기변색소자(ECD)에 응용하였다. SEM, XRD, UV-Vis등을 이용하여 재료학적 분석을 시행하였으며, 전기화학적 테스트로 cyclic voltammetry를 측정 하였다. 그 결과 TNT 분말은 직경 약 20~30 nm, 길이 약 500~600 nm 의 입자형상을 나타내었으며, X-선 회절시험결과 $H_2Ti_2O_5{\cdot}H_2O$의 층상구조를 나타내었다. 제조된 막은 FTO glass 위에 PEI/(TNT/TBAOH)$_{n-1}$/PDDA의 순으로 코팅되었다. 전기화학적 테스트를 위하여 2전극 시스템을 제작하였으며, 여러 종류의 액체 전해질을 제작하여 cycle voltammetry를 시행하였다. 그 결과, 각각의 전해질에서 "-"영역의 산화환원전위 피크가 뚜렷하게 나타났으며, 짙은 갈색으로의 채색현상을 나타냈다. 본 연구의 결과로서 TNT 박막을 이용한 ECD은 광조절 유리로서 뿐만 아니라, 여러 전기채색 디바이스에 응용될 것으로 사료된다.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1293-1296
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• 2007

An amenity requirement of the passenger using public traffic is rising continuously, and also The Ministry of Environment established "Indoor air quality management guidelines in public facilities(Dec. 2006)". To satisfy such requirement, the photoplasma device to decrease VOCs(Volatile Organic Compounds) and suspended bacillus is applied to the underframe mounted HVAC(Heating, Ventilating and Air-Conditioning) system for train. Air purifying method of photoplasma device is optical and chemical reaction that UV-light(wavelength less than 280nm) react with catalyst material(TiO2). To analyze the efficiency of photoplasma in this study, we measured the requirement time for toluene to decease down to 0.3ppm after contaminating the passenger cabin for train to toluene 1ppm.