• Journal of the Korean Ceramic Society
• /
• v.40 no.9
• /
• pp.902-908
• /
• 2003

Au/TiO$_2$ core-shell structure nanoparticles were synthesised by sol-gel process, and the morphology and crystallinity of TiO$_2$ shell were investigated by TEM and UV-Vis. absorption spectrometer. Au/TiO$_2$ core-shell structure nanoparticles could be prepared by the hydrolysis of TOAA (Titanium Oxide Acethylacetonate) in Au colloid ethanol solution with $H_2O$. The thickness of TiO$_2$ shell on the surface of Au particles was about 1 nm. To investigate the crystallinity of TiO$_2$ shell, UV light with 254 nm and radioactive lay of $^{60}$ CO were irradiated on the TiO$_2$ coated Au colloid ethanol solution. The surface plasmon phenomenon of Au nanoparticles appeared only when the radioactive lay was irradiated on the TiO$_2$ coated Au colloid ethanol solution. From these results, it was found that the TiO$_2$ shell was amorphous and the MUA (Mercaptoundecanoic Acid) layer on the Au particle for its dispersion didn't act as an obstacle to disturb the movement of electron onto the surface of Au particle.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.12 no.2
• /
• pp.110-114
• /
• 2002

The relationship between the orientation of molecules adsorbed on $_TiO2$ and their photoproducts was examined by employing HBPCA (4-hydroxy-biphenylcarboxylic acid) as a model organic pollutant. For this purpose, the Photoproducts after irradiation with UV radiation at various pH were compared by utilizing UV and Raman spectroscopies. It was found from these studies that pH affected the photoproducts probably due to the different orientations of the adsorbed molecules, and that the orientation of the adsorbed molecules and their photoproducts were closely correlated.

• Journal of Environmental Health Sciences
• /
• v.28 no.5
• /
• pp.59-64
• /
• 2002

The photocatalytic decolorization of the Rhodamine B (RhB) was studied using a UV/TiO$_2$ reactor. Yakuri titanium dioxide(anatase) was used as the suspended photocatalyst and proved to be effective for decolorization irradiated with UV light (254 mm). The photocatalyzed dioxide concentrations, light intensity and air flow rates. In 0.01 mM RhB, color could be completely photodegraded after 3 hours. Absorption spectrum of an aqueous solution containing RhB showed a continued diminution of the RhB concentration in the solution bulk : concomitantly, no new absorption peaks appeared. This confirmed the decolorization of RhB, i.e., the break up of the chromopore. The optimum loaded titanium dioxide for the decolorization was 0.75 g/(equation omitted). The light intensity showed exponential decay with distance. The decay of light intensity of RhB solution showed different tendency from TiO$_2$. These results suggested that the photocatalytic decolorization of dyes may be available method for decolorizing in wastewater.

• Journal of Environmental Health Sciences
• /
• v.29 no.1
• /
• pp.51-61
• /
• 2003

Pollution purification using titanium dioxide (TiO$_2$) photocatalyst has attracted a great deal of attention with increasing number of relent environmental problems. Currently, the application of TiO$_2$ photocatalyst has been focused on purification and treatment of waste water. However. the use of conventional TiO$_2$ powder photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we herein studied the pilot-scale design to aid in optimization of the energy-saving process for more through development and reactor design by solar light/UV lamp/ TiO$_2$system. In this study, we manufactured the TiO$_2$sol by sol-gel method. According to analysis by XRD, SEM and TEM, characterization of TiO$_2$ sol were nano-size (5-6 nm) and anatase type. Inorganic binder (SiO$_2$) was added to TiO$_2$ lot to be coated for support strongly, and support of ceramic bead was used to lower separation rate that of glass bead The influences were studied of various experimental parameters such as TiO$_2$ quantity, pH, flow rate. additives, pollutants concentration, climate condition and reflection plate by means of reaction time of the main chararteristics of the obtained materials. In water treatment system, variable realtor as solar light/ or UV lamp according to climate condition such as sunny and cloudy days treated the phenol and E-coli(Escherichia coli) effectively.

• Applied Chemistry for Engineering
• /
• v.24 no.3
• /
• pp.231-238
• /
• 2013

In this study, the $TiO_2$ nano spheres were synthesized by Sol-gel method to give an excellent UV-blocking effect and increase waste adsorption. The pH value was adjusted to obtain a superb UV-blocking effect and adsorption capacity due to the high surface area which is the characteristics of porosity. Base treated $TiO_2$ showed outstanding characteristics. The adsorption of gycerine onto the $TiO_2$ sample using TGA resulted in a high surface area of 1.16 mg/mg. This also showed a high reflectance in the UV-A region. In order to find the optimum dispersion, inorganic powder particles were maintained their sizes as 180 nm for about 6 months. The size of particles were measured using ester oil and silicon oil. Overall, the results reveal that $TiO_2$ has an excellent capability sunscreen in the UV-A region and skin waste adsorption.

• Journal of the Korean Applied Science and Technology
• /
• v.23 no.2
• /
• pp.153-159
• /
• 2006

The photocatalytic degradation of methylene blue(MB) was investigated using $TiO_2$ as photocatalyst and UV radiation. $TiO_2$ supported with activated carbon(AC) was prepared by SOL-GEL method and depended on several parameters such as the mass ratio of $TiO_2/AC$, pH and experimental time. The presence of the anatase and rutile crystal phase was determined by XRD analyses of the prepared $TiO_2$. The degradation of MB with $TiO_2/AC$ was about 20% higher than that of AC alone. A variation of photodegradation was negligible under UV radiation conditions ( ${\geq}$ 40W). It was experimentally showed that the photodegradation rate was increased with increasing the amount of photocatalyst. The optimal catalyst was prepared by impregmation of $5wt%-TiO_2$ with AC and was calcined at $300^{\circ}C$, and showed about 99% removal efficiency for 3hrs.

• Journal of Korean Society on Water Environment
• /
• v.16 no.4
• /
• pp.445-457
• /
• 2000

This study was carried out comparing with ozone oxidation and photocatalytic degradation for removal of geosmin. In the change of pH, Ozonation, UV-Germicidal lamp and Halogen lamp irradiation and Halogen $lamp/TiO_2$ Powder was very slowly changing, but UV-Germicidal $lamp/TiO_2$ Powder was rapidly changed from 7.0 to 7.7 until 300min of irradiation time, and varied a little after. Geosmin degradation ratio was as following, UV-Germicidal $lamp/TiO_2$ $Powder(200mg/L){\geq}O_3$ > UV-Germicidal $lamp/TiO_2$ $Pw(100mg/L)$ > UV-Germicidal lamp > Halogen lamp. The result of investigation of generated by-products were 3-Heptanone, two sort of aldehydes and three sort of alcohols by ozonation. But It was not generated by photocatalytic degradation.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.4
• /
• pp.925-928
• /
• 2010

Nitrogen-doped $TiO_2$ ($TiO_2$:N) nano-particles with a pure anatase crystalline structure were successfully synthesized through the hydrolysis of $TiCl_4$ in an ammonia aqueous solution. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), $N_2$-sorption, and UV-vis diffuse reflectance spectra (UV-vis DRS) techniques. The absorption edge of nitrogen-doped $TiO_2$ shifted into the visible wavelength region. The photoelectrochemical (PEC) performances were investigated for the $TiO_2$ mesoporous electrodes doped with different nitrogen concentrations. The $TiO_2$:N electrodes exhibited much higher PEC responses compared to the pure $TiO_2$ electrode because of the significantly enhanced visible-photoresponsibility of the $TiO_2$:N electrodes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.511-511
• /
• 2007

Low-emissivity (low-e) coatings with visible transparency have attracted increased interest m reducing heat radiation loss through window panes from ecological and sustainable aspects. $TiO_2$-silver transparent thin films for low-e have good properties for UV and IR blocking as well as photocatalyst compared to that with commercial UV blocking films such as fluorine doped oxide (FTO), antimony doped tin oxide (ATO), etc. In this study, transparent $TiO_2$-silver thin films were prepared by successive ink-jet printing of commercial nano silver and $TiO_2$ sol. The $TiO_2$ sol, as ink for ink-jet printing, were synthesized by hydrothermal process in the autoclave externally pressurized with $N_2$ gas of 200 bar at $120^{\circ}C$ for 10 hrs. The synthesized $TiO_2$ sols were all formed with brookite phase and their particle size was several to 30 nm. At first nano sized silver sol was coated on glass substrate, after that $TiO_2$ sol was coated by ink-jet printing. With increasing coating thickness of $TiO_2$-silver multilayer by repeated ink-jet coating, the absorbance of UV region (under 400nm) and IR region (over 700nm) also increase reasonably, compared to that with commercial UV blocking films.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2001.11a
• /
• pp.82-83
• /
• 2001

LAS(Linear Alkylbenzene sulfonate)를 $TiO_2$ 광촉매를 사용하여 분해시켰을 때 실험조건에 변화를 주어 반응시간에 따른 제거효율을 비교하는 실험을 수행하였다. pH 변화에 의해서는 산성과 중성 영역이 알카리성 영역에 비해 제거효율이 우수하였으며, 파장영역은 254nm > 312nm > 365nm의 순서로 나타났다. UV/$TiO_2$ 공정과 UV/$TiO_2$$H_2O_2$공정을 비교해보면 $H_2O_2$의 첨가에 의한 제거효율이 다소 우수함을 알 수 있었다.