• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.279-284
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• 2006

Photo-catalytic products have been widely used at home and hospital to prevent bacteria, virus and fungus. Activities of anti-bacteria, anti-viruses and anti-fungi are based upon direct contact of crystals and particles of titanium dioxide with pathogens, into which titanium is catalyzed by photo. Those antimicrobial activities of the photo-catalytic titanium dioxide have been proved in vitro. However, in vivo tests of those activities have not been carried out on dog skin. Aim of this study was to evaluate the antimicrobial activities of the catalytic titanium dioxide in vivo. Ten beagle dogs were divided into two groups. One group was sprayed with 10ml of titanium dioxide(1 mg/ml) whereas the other was not. The treated dogs were exposed under the sunlight for 120 min. A set of three hairs was taken 15, 30, 60 and 120 min after the exposure and the bacteria contaminated in hairs were amplified in, Muller Hilton broth at $35^{\circ}C{\pm}1$ for 3 h. The supernatant of the bacterial culture was diluted 1 : 10 in phosphafe-buffered saline. One milliliter of the diluents was transferred into triphenyltetrazolium medium(TTC) and incubated at $35^{\circ}C{\pm}1$ for 2 days. The number of bacteria was counted. The number of bacteria colonies was decreased compared to control group. To further investigate the longevity effect of titanium dioxide, the dogs were kept in indoor without sun light for 6 and 12 h, 1, 2, 3, 7, 14 days after exposure of the chemical during each 15, 30, 60 min. The number of bacteria colony in 1ml was counted. The number of bacterial colonies was decreased. Treated group is exposured by sun light during 15 min, the longevity effect of titanium dioxide is continued by 1 week. Treated group is exposured by sun light during 30, 60 min, the longevity effect of titanium dioxide is continued over 2 weeks. These data indicated that the photo-catalytic titanium dioxide may be used for prevent bacteria on dog skin.

• Journal of the Korean Ceramic Society
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• v.52 no.3
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• pp.221-223
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• 2015

In this work, we report on the preparation of the anodically-grown $TiO_2$ nanotube arrays sensitized with $In_2S_3$ nanoparticles by using the SILAR (successive ionic layer adsorption and reaction) process. We evaluate the photo-catalytic properties of the prepared hetero-structures under visible-light illumination. The results reveal that the $TiO_2/In_2S_3$ system has enhanced photo-catalytic characteristics including higher chopping height. Improved performance of the heterojunction is attributed to the narrower band gap of $In_2S_3$ and its favorable position within the conduction band relative to that of $TiO_2$.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.1-10
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• 2010

This is an overview paper reporting our most recent work on processing and microstructure of nano-structured oxides and their photoluminescence and photo-catalysis properties. Zinc oxide and related transition metal oxides such as vanadium pentoxide and titanium dioxide were produced by a combination of magnetron sputtering, hydrothermal growth and atmosphere controlled heat treatment. Special morphology and microstructure were created including nanorods arrays, core-brushes, nano-lollipops and multilayers with very large surface area. These structures showed special properties such as much enhanced photoluminescence and chemical reactivity. The photo-catalytic properties have also been promoted significantly. It is believed that two factors contributed to the high reactivity: the large surface area and the interaction between different oxides. The transition metal oxides with different band gaps have much enhanced photoluminescence under laser stimulation. Use of these complex oxide structures as electrodes can also improve the energy conversion efficiency of solar cells. The mixed oxide complex may provide a promising way to high-efficiency photo emitting materials and photo-catalysts.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.286-291
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• 2001

As part of fundamental studies on the degradation of the organic compounds in industrial waste water, the photocatalytic degradation properties of the organic compound by means of the UV/TiO$_2$degradation process have been investigated. The test organic compound of acetic acid was chosen in this study. The testing of photo catalytic degradation were performed under various operation conditions such as TiO$_2$dosages, initial concentration of the organic, the aqueous pH's, etc. The effects of various parameters on the short time activity of the present acetic acid-UV/TiO$_2$system could be demonstrated from this investigation.

• Journal of the Korean institute of surface engineering
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• v.40 no.3
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• pp.113-116
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• 2007

Titanium dioxide ($TiO_2$) films were deposited by RF reactive magnetron sputtering on non-alkali glass and single crystal MgO (100) substrate at substrate temperature of $400^{\circ}C$. Micro structures of $TiO_2$ films were investigated by XRD, FE-SEM, and Pole figure measurements. $TiO_2$ films deposited on glass substrate showed preferred orientation of anatase (101), whereas $TiO_2$ films deposited on the MgO single crystal substrate showed hetero-epitaxial anatase (100). $TiO_2$ film grown on MgO substrate showed higher photoctalytic activity than that of glass substrate.

• Journal of the Korean Applied Science and Technology
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• v.24 no.1
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• pp.1-9
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• 2007

It prepared the $TiO_2$ powder which has photo-catalytic activity in the visible-light by the wet process with titanium oxysulfate. The titanium $dioxide(TiO_2)$ by the wet process creates a new absorption band in the visible light region, and is expected to create photocatalytic activity in this region. Anatase $TiO_2$ powder which has photocatalytic activity in the visible light region, is treated using microwave and radio-frequency(RF) plasma. But, the $TiO_2$ powder for the visible light region, which also can be easily produced by wet process. The wet process $TiO_2$ absorbed visible light between 400nm and 600nm, and showed a high activity in this region, as measured by the oxidation removal of aceton from the gas phase. The AH-380 sample appears the yellow color to be strong, the catalytic activity in the visible ray was excellent in comparison with the plasma-treated $TiO_2$. The AH-380 $TiO_2$ powder, which can be easily produced on a large scale, is expected to have higher efficiency in utilizing solar energy than the plasma-treated $TiO_2$ powder.

• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.531-534
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• 2015

In this work, we undertake a comparative study of the crystallographic microstructures and photo-catalytic properties of rutile $TiO_2$ nanorods grown on FTO facing up and down by a hydrothermal method. An analysis of the fine structures showed that $TiO_2$ nanorods grown on FTO facing up were mixed with sea urchin and microsphere. These structures induced a vertical orientation of the nanorods on FTO. The saturated photocurrent densities of the $TiO_2$ nanorods grown both up and down were $1.5mA/cm^2$ in the former case, the IPCE was increased to 10% at 300~350 nm. The onset potential (${\fallingdotseq}$ flat band potential) of the nanorods grown on FTO facing up is negatively shifted to a value of -0.31 V. This is caused by an increase in the surface state, in this case the number of oxygen vacancies, and by the formation of $Ti^{3+}$. Therefore, the FTO facing direction is considered as a critical factor during the hydrothermal reaction for $TiO_2$ growth so as to develop an efficient photo-catalytic system.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.29-38
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• 2015

Cyanide can be leached out from the cyanidation method which has been used to extract high-purity gold and silver from ores, and it becomes a variety of cyanide complexes associated with heavy metals contained in ores. Such cyanide complexes are considered as persistent and non-degradable pollutants which cause adverse effects on humans and surrounding environments. Based on binding force between heavy metals and cyanide, cyanide complexes can be categorized weak acid dissociable (WAD) and strong acid dissociable (SAD). This study comparatively evaluated the performance of photo-catalytic process with regard to forms of cyanide complexes. In particular, both effects of UV LED wavelength and surface modification of photo-catalyst on the removal efficiency of cyanide complexes were investigated in detail. The results indicate that the performance of photo-catalytic oxidation is significantly affected by the form of cyanide complexes. In addition, the effect of UV LED wavelength on the removal efficiency was quite different between free cyanide and cyanide complexes associated with heavy metals. The results support that the surface modification of photo-catalyst, such as doping can improve overall performance of photo-catalytic oxidation of cyanide complexes.

• Carbon letters
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• v.9 no.4
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• pp.294-297
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• 2008

A CNT-$TiO_2$ nano composite was prepared from titanium chloride ($TiCl_4$) via sol-gel process using multi walled carbon nano tube (MWCNT) followed by calcination at $450^{\circ}C$. Spectral analysis revealed that the formed $TiO_2$ resided on the carbon in anatase form. The effect of adsorption was investigated using aqueous solution of methylene blue and procion blue dye. The photochemical reaction of CNT-$TiO_2$ composite in aqueous suspensions was studied under UV illumination in batch process. The reaction was investigated by monitoring the discoloration of the dyes employing UV-Visible spectro-photometeric technique as a function of irradiation time. The catalyst composites were found to be efficient for the photodegradation of the dye.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.223-233
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• 2014

Cyanidation method has been used to extract high-purity gold and silver in mining industry. Such mining activities have used a large amount of cyanide, and the mine wastewater contained a high level of cyanide has brought about pollution of surrounding aqueous environments. This research was initiated to study $TiO_2$-catalytic UV-LED photo-oxidation to remove cyanide from the mine wastewater. UV lamp has been generally used as a light source in conventional photo-oxidation so far, but it shows numerous drawbacks. For this reason, this study focused on the evaluation of applicability of UV-LED as an alternative light source in cyanide photo-oxidation process. Three types of $TiO_2$ photo-catalyst were compared in terms of performance of photo-oxidation of cyanide, and the results show that Degussa P25 was the most efficient. In addition, four types of UV-LED were tested to compare their efficiencies of cyanide photo-oxidation, and their efficacy was increased in the order of 365 nm lamp-type > 365 nm can-type > 280 nm can-type > 420 nm lamp-type. Not only did this study demonstrate that UV-LED can be used in the photo-oxidation of cyanide as an alternative light source of UV lamp, but also confirmed that the performance of photo-oxidation was significantly influenced by the type of $TiO_2$ catalysts.