• Clean Technology
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• v.11 no.3
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• pp.123-128
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• 2005

Among various metal oxides semiconductors, $TiO_2$ is the most studied semiconductor for environmental clean-up applications due to its unique ability in photocatalyzing various organic contaminants, its chemical inertness, and nontoxicity. $TiO_2$, however, has a few drawbacks to be solved such as reactivity mainly working under ultraviolet irradiation (${\lambda}$ < 387 nm) and electron - hole recombination on $TiO_2$. In this study, to extend the absorption range of $TiO_2$ into the visible range and enhance electron - hole separation, we synthesized platinum (Pt) deposited $C-TiO_2$. The presence of Pt as an electron sink has been known to snhance the separation of photogenerated electron-hole pairs and induce the thermal decomposition. The characterization of as-synthesized $Pt-C-TiO_2$ was performed by Transmission Electron Microscopic (TEM), the Brunuer-Emmett-Teller (BET) method, X-ray Diffractometer (XRD), UV-vis spectrometer (UV-DRS), and X-ray Photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photodegradation experiment of an azo dye (Acid Red 44; $C_{10}H_7N=NC_{10}H_3(SO_3Na)_2OH$)was carried out by using an Xe arc lamp (300 W, Oriel). A 420 nm cut-off filter was used for visible light irradiation. From the results, Pt-deposited $C-TiO_2$ showed a far superior phothdegradation activity to Degussa P25, the commercial product under the irradiation of visible light and enhanced photocatalytic activity of visible-working $C-TiO_2$. This is a useful result into the application for the purification system of dye wastewater using visible energy of sun light.

• Journal of Life Science
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• v.19 no.1
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• pp.94-100
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• 2009

This study was carried out to examine the antimicrobial effects of grapefruit seed extract (GSE) and processed sulfur solution (PSS) against human skin pathogens: Malassezia furfur, M. restricta, Propionibacterium arnes, Trichophyton mentagrophytes and T. rubrum. The antimicrobial effects of GSE and PSS were tested by agar diffusion method and micro broth dilution method. As the results, the MIC values of GSE against M. furfur, M. restricta, P. acnes, T. mentagrophytes and T. rubrum were 3.91, 3.91, 0.004, 0.024, and $0.012{\mu}l/ml$, respectively. The MIC values of PSS were 0.03, 0.03, 0.156, 0.003, and $0.012{\mu}l/ml$, respectively. Antimicrobial activity of skin care emulsion products containing 0.5% GSE and 0.5% PSS against human skin pathogens were 5.2, 4.3, 8.0, 9.5 and 12.8 mm, respectively. Refractive index, pH, viscosity and color value of skin care emulsions containing GSE and PSS were measured. According to these results, it was concluded that the GSE and PSS were the promising sources of antibacterial agent which could be useful for skin and hair care products as well as for the alternative medicine development in treatment of certain types of skin ailments.