• 한국재료학회지
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• 제20권10호
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• pp.535-542
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• 2010

In this study, we used coal-based activated carbons and charcoal as startingmaterials, phenolic resin (PR) as a binder, and TOS as a titanium source to prepare $TiO_2$ combining spherical shaped activated carbon photocatalysts. The textural properties of the activated carbon photocatalysts (SACP) were characterized by specific surface area (BET), energy dispersive X-ray spectroscopy (XRD), scanning electron microscopy (SEM), iodine adsorption, strength intensity, and pressure drop. The photocatalytic activities of the SACPs were characterized by degradation of the organic dyes Methylene Blue (MB), Methylene Orange (MO), and Rhodamine B (Rh. B) and a chemical oxygen demand (COD) experiment. The surface properties are shown by SEM. The XRD patterns of the composites showed that the SACP composite contained a typical single, clear anatase phase. The EDX spectro for the elemental indentification showed the presence of C and O with Ti peaks. According to the results, the spherical activated carbon photocatalysts sample of AOP prepared with activated carbon formed the best spherical shape, a high BET surface area, iodine adsorption capability and strength value, and the lowest pressure drop, and the photocatalytic activity was better than samples prepared with charcoal. We compared the degradation effects among three kinds of dyes. MB solution degraded with the SACP is better than any other dye solutions.

• 한국재료학회지
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• 제19권3호
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• pp.142-150
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• 2009

In this paper, non-treated ACF (Activated Carbon Fiber) /$TiO_2$ and Zn-treated ACF/$TiO_2$ were prepared. The prepared composites were characterized in terms of their structural crystallinity, elemental identification and photocatalytic activity. XRD patterns of the composites showed that the non-treated ACF/$TiO_2$ composite contained only typical single and clear anatase forms while the Zn-treated ACF/$TiO_2$ contained a mixed anatase and rutile phase with a unique ZnO peak. SEM results show that the titanium complex particles are uniformly distributed on and around the fiber and that the titanium complex particles are more regularly distributed on and around the ACF surfaces upon an increase of the $ZnCl_2$ concentration. These EDX spectra show the presence of peaks from the C, O and Ti elements. Moreover, peaks of the Zn element were observed in the Zn-treated ACF/$TiO_2$ composites. The prominent photocatalytic activity of the Zn-treated ACF/$TiO_2$ can be attributed to the three different effects of photo-degradation: doping, absorptivity by an electron transfer, and adsorptivity of porous ACFs between the Zn-$TiO_2$ and Zn-ACF.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.387-392
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• 2005

For the production of further functional bio-degradable plastic(polybutylene succinate:PBS) with $TiO_{2}$ as photocatalyst, which shows the decomposition of detrimental organic compound and pollutant under ultraviolet irradiation, we attempted to prepare $TiO_{2}$ coatings on PBS substrate by HVOF and plasma spraying techniques under various conditions. The microstructures of coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of coatings was evaluated through the photo degradation of gaseous acetaldehyde. The effects of primary particle size and spraying parameters on the formation behavior, photo catalytic performance and mechanical characteristics of the coatings have been investigated. The results indicated that with respect to both the HVOF sprayed $P_{200}$ and $P_{30}$ coatings, the high anatase ratio off 100% can be achieved regardless of fuel gas pressure. On the other hand, the HVOF sprayed $P_{7}$ coating exhibited largely decreased anatase ratio (from 100% to 49.1%) with increasing the fuel gas pressure, which may be attributed to the much higher susceptibility to heat of 7nm agglomerated powder. In terms of photocatalytic efficiency, HVOF sprayed $P_{200}$ and $P_{30}$ coatings seem to predominate as compared to that of plasma sprayed $P_{200}$ coatings owing to the higher anatase ratio. However, the HVOF sprayed $P_{7}$ coatings didn't show the photo catalytic activity, which may result from the extremely small reaction surface area to the photo-catalytic activity and low anatase ratio. Such functional PBS with new roles is expected to cosiderably contribute to the reduction of aggravated environmel problem.

• 한국건설순환자원학회논문집
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• 제11권4호
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• pp.493-500
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• 2023

본 연구에서는 전도성 재료를 혼입한 광촉매 보도블록을 제조하여 질소산화물 제거율에 미치는 영향을 살펴보고 내구성이 향상된 블록을 제조하고자 하였다. 광촉매와 전도성 재료인 활성탄소를 혼입시 광촉매 효율이 향상되었으며 전도성 광촉매 콘크리트 블록의 경우 광촉매 콘크리트 블록보다 질소산화물 제거율이 2.5배 정도 향상되었다. 전도성 광촉매 시험편의 질소산화물 제거율이 높게 나타난 것은 전도성 재료인 활성탄소의 영향으로 TiO₂ 광분해로 인한 광전류가 많이 발생한 영향으로 볼 수 있으며 광촉매 시험편과 전도성 광촉매 시험편의 질소산화물 제거율 실험결과와 광전류 시험결과를 비교 분석하였다.

• 산업기술연구
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• 제21권B호
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• pp.21-26
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• 2001

In this study, the effects of crystalinity, composition and particle size of $TiO_2$ catalysts on the degradations of humic acid in aqueous solution was assessed using the commercially avaliable $TiO_2$ particles. Photocatalytic oxidations of humic acid (HA, Aldrich Co.) solution were carried out in case of adding different types of $TiO_2$ catalysts and their decomposition efficiencies were analyzed with respect to pH, DOC and UV absorbances values for the HA solutions and compared one another. The experimental results showed that $TiO_2$ particles(Degussa P-25) mixed with anataze and rutile gave the highest degradation efficiencies, respectively and much lower degradation efficiency in $TiO_2$ paticles of rutile only type. In comparing among ST series of anataze types, it was observed that the degradation efficiencies generally were increased with increasing $TiO_2$ contents and surface area of the particles. Higher degradation efficiency of HA was also found in zeolite type(D-TZ) of $TiO_2$ paticles compared with hydroxyapatite type (D-TH) of $TiO_2$ particles.

• 한국환경과학회지
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• 제15권6호
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• pp.593-600
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• 2006

SIS triblock copolymers, one of the major raw materials of oil gelling agent, were synthesized by living anionic polymerization and the resultant copolymers formed with various shapes and sizes were used to examine their oil gelling capacities. Coupling method was adapted to form final triblock products from diblock living polymers. Prior to polymerization, the impurities in monomers and solvents were throughly removed by killing technique. We experimentally investigated the effects of operating parameters of synthesis and forming of SIS triblock copolymers on oil gelling capacity. The photocatalytic decomposition of SIS triblock copolymer under ultraviolet circumstance was also investigated and it is found that the addition of P-25 enhances the photocatalytic decomposition.

• Environmental Engineering Research
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• 제14권1호
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• pp.32-40
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• 2009

In this study, we have prepared three kinds of carbon nanometer tube $CNT/TiO_{2}$ electrodes through impregnation with different concentration titanium n-butoxide (TNB) solution. The prepared electrodes were characterized with surface properties, structural crystallinity, elemental identification and photoelectrocatalytic activity. The $N_2$ adsorption data showed that the composites had decreased surface area compared with the pristine CNT. This indicated the blocking of micropores on the surface of CNT, which was further supported by observation via SEM. XRD results showed patterns for the composites and a typical single and clear anatase crystal structure. The main elements such as C, O and Ti were existed for all samples from the EDX data. The catalytic efficiency of the developed electrode was evaluated by the photoelectrodegradation of methylene blue (MB). The positive potential applied in photoelectrocatalytic (PEC) oxidation was studied. It was found that photoelectrocatalytic (PEC) decomposition of MB solution could be attributed to combination effects between $TiO_2$ photocatalytic and CNT electro-assisted. Through the comparison between photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation, it was found that the PEC oxidation efficiency for MB is higher than that of PC oxidation.

• 한국입자에어로졸학회지
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• 제5권1호
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• pp.1-7
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• 2009

Fe- and V-doped titanium dioxide nanoparticles consisting of spherical primary nanoparticles were synthesized from a mixed liquid precursor by using the flame spray pyrolysis. The effects of dopant concentration on the powder properties such as morphology, crystal structure, and light adsorption were analyzed by TEM, XRD, and UV-Vis spectrophotometer, respectively. As the V/Ti molar ratio increased, pure anatase particles were synthesized. On the contrary, rutile phase particles were synthesized as the Fe/Ti ratio increased. Photocatalytic property of as-prepared $TiO_2:Fe,V$ nanoparticles was investigated by measuring the removal efficiency for volatile organic compounds (VOCs) under the irradiation of visible light. After 2 hrs under visible light, the removal efficiencies of benzene, p-xylene, ethylbenzene, and toluene were reached to 21.9%, 21.4%, 19.8% and 17.6% respectively.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.47-53
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• 2000

To overcome the shortage of conventional TWC that is activated at high temperature, higher than 25$0^{\circ}C$, photocatalyst is considered as an new technology. Because the photocatalytic reaction of photocatalyst is not a thermo mechanical reaction, it is necessary to heat the system to start the reaction. It can be activated just by ultra violet light that includes wavelengths shorter than 400 nanometers even at ambient temperature. In this study photocatalytic reduction of hydrocarbon was investigated with a model gas test. To understand the effects of co-existence gases on the hydrocarbon reduction by photoreaction, CO and NO, $O_2, H_2O$ gases those are components of exhaust gases of gasoline engine are supplied with C3H8/N2 to a photoreactor. The photoreactor contains $TiO_2$ photocatalyst powders and a UV bulb. The results show that oxygen is the most important factor to reduce HC emission with photocatalyst. Photocatalyst seems to have a good probability for automotive application to reduce cold start HC emissions.

• 한국분말재료학회지
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• 제11권2호
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• pp.143-148
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• 2004

In the present study, $TiO_2$ imbedded composite powders have been successfully prepared from the (Cu. Zn)/$TiO_2$ composite salt solution. The composite (Cu, Zn)/$TiO_2$ powders were formed by drying the solution at 200~$600^{\circ}C$ in the hydrogen atmosphere. Photocatalytic characteristics was evaluated by detecting the decomposition ratio of aniline blue with UV-visible spectrophotometer(Shimazu Co., UV-1601). Phase analysis of (Cu, Zn)/$TiO_2$ composite powders was carried out by XRD and DSC, and powder size was measured with TEM. The mean particle size of composite powders was about 100mm. As the reduction temperature increases, a few zinc sulfide and oxide phases was formed and copper oxide phase was reduced. The decomposition ratio of aniline blue was about 80％ under the UV irradiation by the TiO$_2$ phase in the composite (Cu, Zn)/$TiO_2$ powders and similar decomposition ratio of 80％ was obtained at the UV lightless condition by virtue of Cu and Zn compounds.