• Journal of the Korean Ceramic Society
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• v.48 no.4
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• pp.282-287
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• 2011

ACF and $WO_3$ modified $TiO_2$ composites (ACF/$WO_3$/$TiO_2$) were prepared using a sol-gel method. The composites were characterized by Brunauer.Emmett.Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of the MO was determined using UV/Vis spectrophotometry. An increase in photocatalytic activity was observed and attributed to an increase of the photo-absorption effect by the $WO_3$ and the cooperative effect of the ACF.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.133-138
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• 2004

The photodegradation of phenol and toluene with the $TiO_2$-coated polyethylene (PE) particles were investigated in the slurry type photocatalytic reactor, changing the $TiO_2$ particle sizes, initial phenol and toluene concentrations, and the oxygen flow rate. The nano-sized $TiO_2$ photocatalyst particles were prepared by the diffusion flame reactor and they were coated onto PE particles by using the hybridization system for the efficient recollection of $TiO_2$-coated particles after photodegradation experiments. The degradation efficiencies of phenol and toluene with the $TiO_2$-coated PE particles were more than 90% after photodegradation of 80 minutes for most cases. The efficiencies of photodegradation with the $TiO_2$-coated PE particles were found to be lower than those by the pure $TiO_2$ particles by 50%, because of the decrease in specific surface area of $TiO_2$ particles in PE particles.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.431-438
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• 2006

The strength, water permeability, and photo-degradation efficiency of NOx of porous concrete with a new concept were studied in this paper. The porous concrete was comprised of coarse aggregate of maximum size 40 mm, cement, silica fume, water and air-entraining(AE) water reducing agent. The strength of porous concrete was strongly related to its matrix proportion and compaction energy. An experimental test was carried out to study the parameters of cement proportions and silica fume content for pavement applications of porous concrete which were paving a footpath, a bikeway, a parking lot, and a driveway. The regressed equations of relation-ships between compressive strength and flexural strength, and coefficient permeability and void ratios were indicated as y=7.69x+71.74 and $y=0.42e^{0.28x}$. A method of making an air purification-functioning road, which was spraying a mixture of a photocatalyst, cement, and water onto the surface of the road, was suggested.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.571-576
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• 2011

Activity carbon (AC), Cu and $Cu_2O$ modified $TiO_2$ composites (Cu/$Cu_2O$-AC/$TiO_2$) were prepared using a sol-gel method. The characteristics of the composites were evaluated using Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of MO was determined using UV/Vis spectrophotometry. $Cu_2O$, Cu and the cooperative effect of the AC increased the photo-absorption effect, thus increasing in photocatalytic activity.

• Toxicological Research
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• v.33 no.2
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• pp.125-134
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• 2017

The effects that ultraviolet rays elicit on collagen synthesis and degradation are the most common causes of wrinkle formation and photo-aging in skin. The objectives of this study were to evaluate the effects of Angelica acutiloba root ethanol extract (AAEE) to promote collagen synthesis and inhibit collagen degradation in human dermal fibroblasts. By examining total polyphenol and flavonoid contents, electron donating ability, radical scavenging activity, and superoxide dismutase-like activity, we found that AAEE exhibited fairly good antioxidant activity. Treatment with AAEE significantly increased type I procollagen production by cultured fibroblasts, as well as reduced ultraviolet-induced matrix metalloproteinase-1 (MMP-1) expression and MMP-2 activity in a dose-dependent manner (p < 0.05). In addition, AAEE significantly increased TIMP-1 mRNA expression (p < 0.05), although without an associated dose-dependent increase in TIMP-1 protein expression. In summary, we suggest that AAEE may be a potentially effective agent for the prevention or alleviation of skin-wrinkle formation induced by ultraviolet rays.

• Journal of the Korean Ceramic Society
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• v.45 no.11
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• pp.667-674
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• 2008

In this study, we prepared Fe-activated carbon fiber(ACF)/$TiO_2$ composites with titanium (VI) n-butoxide (TNB) as the titanium source for ACF pre-treated with iron compounds through the impregnation method. In terms of textural surface properties, the composites demonstrate a slight decrease in the BET surface area of the samples and an increase in the amount of iron compounds treated. The surface morphology of the Fe-ACF/$TiO_2$ composites was characterized by means of SEM. The composites have a porous texture with homogenous compositions of Fe and titanium dioxide distributed on the sample surfaces. The phase formation and structural transition of the iron compounds and titanium dioxide were observed in X-ray diffraction patterns of the Fe-ACF/$TiO_2$ composites. The chemical composition of the Fe-ACF/$TiO_2$ composites, which was investigated with EDX shows strong peaks for the C, O, Fe and Ti elements. The photo degradation results confirm that the Fe-ACF/$TiO_2$ composites show excellent removal activity for the COD in piggery waste due to photocatalysis of the supported $TiO_2$, radical reaction by Fe species, and the adsorptivity and absorptivity of ACF.

• Polymer(Korea)
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• v.26 no.4
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• pp.431-438
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• 2002

We studied the orientation behavior and thermal stability of polyimide (PI) molecules under irradiation of polarized UV (PUV) using polarized fourier transform infrared (FTIR) spectroscopy. In the case of PUV-exposed PI films, the remaining PI molecules after photo-degradation showed molecular orientation perpendicular to the irradiated PUV polarization direction predominantly, due to the preferential degradation of PI molecules parallel to the irradiated PUV Polarization direction. On the other hand, the rubbing of PI films induced reorientation of the PI molecules parallel to the rubbing direction. We also investigated the thermal stability of the alignment layers furled by rubbing and PUV irradiation on the PI films using Polarized FTIR. The thermal stability of the PUV irradiated PI alignment layer is lower than that of the rubbed PI layer due to the fragmentation reaction of the PI by PUV.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.133-139
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• 2010

Photoelectrocatalytic decolorization of methlene blue (MB) in the presence of two types of carbon nanotube/titania and yttrium-treated carbon nanotube/titania electrodes in aqueous solutions were studied under visible light. The prepared composite electrodes were characterized by X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray analysis, and photoelectrocatalytic activity. The photoelectrocatalytic performances of the supported catalysts were evaluated for the decolorization of MB solution under visible light irradiation. The results showed that yttrium incorporation enhanced the decolorization rate of MB. It was found that the photoelectrocatalytic degradation of a MB solution could be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube network, the enhancement of yttrium and a function of the applied potential. The repeatability of photocatalytic activity was also tested. The presence of yttrium enhanced the hydrophillicity of yttrium-carbon nanotubes/titania electrode because more OH groups can be adsorbed on the surface.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.1
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• pp.35-42
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• 2010

In this paper, three types of CNT/$TiO_2$ composite electrodes were prepared with different methods. The changes in XRD patterns showed that the Electrode A contained a mixed phase of anatase and rutile while the Electrode B and Electrode C contained a typical single and clear anatase crystal structure. From SEM micrographs, $TiO_2$ particles were adhered on the surface of the CNT network in the forms of small clusters. The results of chemical elemental analysis indicated that the main elements such as C, O and Ti were existed. The results demonstrated that the efficiency of photoelectrocatalytic (PEC) oxidation for methylene blue (MB) was higher than that of photocatalytic (PC) oxidation. There was a clear enhancement trend of the MB degradation using the prepared CNT/$TiO_2$ composite electrodes with an increase of applied potential. Finally, the prominent PEC activities of the CNT/$TiO_2$ composites could be attributed to combination effects of photo-degradation of $TiO_2$, electron assistant of CNT and function of applied potential.

• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.433-438
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• 2011

In this study, CdS combined activated carbon/$TiO_2$ (CdS-AC/$TiO_2$) composites were prepared by a sol-gel method to improve the photocatalytic performance of $TiO_2$. These composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV-vis analysis. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible light irradiation. The photodegradation rate of MB under visible light irradiation reached 90.1% in 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The 0.2 CAT sample showed the best photocatalytic activity, which might be due to an increase in the photo-absorption effect by activated carbon and the cooperative effect of CdS.