• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.172-173
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• 2021

With the development of nano-reinforcement technology and the increasing concern for environmental issues, TiO₂ nanomaterials have received wide attention as an additive besides carbon nanomaterials that can be used to enhance the mechanical properties of cement-based materials. Also, TiO₂-based materials can allow cement-baned materials with photocatalytic capability, providing a potentially effective approach to reduce environmental problems. In this work, compressive strength, splitting tensile strength, and degradation of methylene blue solution were used as target to assess the effect of TiO₂ nanotubes on the mechanical strength and photocatalytic effect of hardened cement paste at different curing time. According to the strength results, the optimum amount of TiO₂ was identified as 0.5% of the weight of cement. Meanwhile, the TiO₂ nanotubes-reinforced specimen exhibited better photocatalytic effect in the early stage of curing.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.85-86
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• 2020

With the increasing importance of environmental issues, the cementitious materials with self-cleaning or photocatalytic properties by introducing TiO₂ materials have been gaining a lot of attention. In this work, the influence of TiO₂ particle size and structure on its photocatalytic effect in cement paste was investigated. The degradation of methylene blue solution was used as the parameter for evaluating the photocatalytic effect of micro-TiO2 (m-TiO₂), nano-TiO2 (n-TiO₂), and TiO₂ nanotube (TNT). Moreover, the effect of these three TiO₂ materials on the cement hydration products was characterized by X-ray diffraction (XRD) and thermgravimetric analysis (TG). According to the results, it can be found that all of the TiO₂ materials promoted the formation of hydration products, especially TNT. On the other hand, the m-TiO₂ exhibited a better photocatalytic effect compared to other materials.

• 한국염색가공학회지
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• 제25권2호
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• pp.94-101
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• 2013

Poly(acrylonitrile) (PAN) nanofibers containing different amounts of titanium dioxide ($TiO_2$) have been prepared by electrospinning technique. Photocatalytic activity of these electrospun PAN/$TiO_2$ nanofibers and the effect of $TiO_2$ content on the photocatalytic efficiency of PAN/$TiO_2$ nanofibers have been evaluated by monitoring the photodecomposition of fluorescein dye, rhodamine B and methylene blue under UV irradiation with respect to irradiation time. Moreover, the effect of hydrogen peroxide ($H_2O_2$) on the photocatalytic behavior of PAN/$TiO_2$ nanofibers has also been investigated. The results showed that PAN/$TiO_2$ nanofibers are effective photocatalyst and their photocatalytic efficiency increases with the increase of $TiO_2$ content in the PAN/$TiO_2$ nanofibers. It is also observed that the presence of $H_2O_2$ significantly enhances the photocatalytic ability of PAN/$TiO_2$ nanofibers. The morphology and the photocatalytic behavior of the PAN/$TiO_2$ nanofibers containing different amounts of $TiO_2$ nanoparticles have been investigated by field-emission scanning electron microscopy (FE-SEM) and UV/Visible spectroscopy, respectively.

• 한국세라믹학회지
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• 제53권3호
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• pp.343-348
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• 2016

Manganese and $TiO_2$ grown on Activated Carbon Fiber (ACF) was synthesized by hydrothermal method. The prepared composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). The catalytic behavior was investigated through the decomposition of methylene blue (MB) and methyl orange (MO) as standard dyes under visible light. The degradation performance of the degraded standard dye solutions was determined by UV-Vis spectrophotometry. This enhanced photocatalytic activity arises from the positive synergetic effect among the Mn, $TiO_2$ and ACF in this heterogeneous photocatalyst. The process contributes to the release of abundant photocatalytic sites of Mn and $TiO_2$ and improves the photocatalytic efficiency. The excellent adsorption and photocatalytic effect with the explanation of the synergetic mechanism are very useful not only for fundamental research but also for potential practical applications.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.164-174
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• 2018

The purpose of this work designed hybrid-structured and plasma effect photocatalyst of $Ag/In_2O_3/TiO_2/HNTs$ via sol-gel and photo-reduction methods. The structures, morphologies, optical and photoelectric performances of as-prepared photocatalysts were characterized via XRD, TEM, XPS, BET, UV-vis DRS, PL and photocurrents. The photocatalytic activity was evaluated by degradation of TC. The results showed that the hybrid-structure and plasma effect can effectively cause the multi-transfer of electrons and increase the separation rate of electron and hole pairs which obtained high photocatalytic activity. The photocatalytic degradation processes reveal that $^{\bullet}O_2{^-}$ and $h^+$ are major active species.

• 한국환경과학회지
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• 제23권6호
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• pp.1151-1156
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• 2014

The photocatalytic decomposition characteristics of single n-pentane, n-pentane mixed with methyl ethyl ketone (MEK), and n-pentane mixed with ethyl acetate (EA) by cylindrical UV reactor installed with $TiO_2$-coated perforated plane were studied. The effects of the residence time, the inlet gas concentration, and the oxygen concentration were investigated. The removal efficiency of n-pentane was increased with increasing the residence time and the oxygen concentration, but decreased with increasing the inlet concentration of n-pentane. The photocatalytic decomposition rates of single n-pentane, n-pentane mixed with MEK, and n-pentane mixed with EA fitted well on Langmuir-Hinshelwood kinetics equation. The maximum elimination capacities of single n-pentane, n-pentane mixed with MEK, and n-pentane mixed with EA were obtained to be $465g/m^3{\cdot}day$, $217g/m^3{\cdot}day$, and $320g/m^3{\cdot}day$, respectively. The presence of coexisting MEK and EA vapor had a negative effect on the photocatalytic decomposition of n-pentane and the negative effect of MEK was higher than that of EA.

• 한국건축시공학회지
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• 제14권4호
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• pp.359-368
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• 2014

Photocatalytic cement has been receiving attention due to its high oxidation power that reduces nitrogen oxide, thus contributing to a clean atmospheric environment. However, there has not yet been a thorough investigation on the effect of photocatalytic reactions on the durability of cementitious material, the parent material. In this study, photocatalytic cement samples were exposed to nitric oxide gas and UV along with cycles of wetting and drying to simulate environmental conditions. The surface of samples was characterized mechanically, chemically, and visually during the cycling. The results indicate that that the photocatalytic efficiency decreased with continued NO oxidation. The pits found from SEM indicated that chemical deterioration, such as acid attack or leaching, did occur. However, this was not confirmed by X-ray diffraction. The hardness was not affected, probably due to the formation of CSH as evidenced by the XRD pattern. In conclusion, it was found that photocatalysis could alter cementitious materials both chemically and mechanically, which could further affect long-term durability.

• Korean Chemical Engineering Research
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• 제50권6호
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• pp.952-959
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• 2012

환형 광촉매반응기 외경지지체의 반사막에 의한 광촉매반응기시스템의 광도를 제고함으로써 개선된 광촉매반응기에 의한 악취성분 및 휘발성 유기화합물을 동시 포함한 폐가스의 처리를 수행하였다. 그리고 광도 제고가 각 운전조건에서의 폐가스처리효율에 미치는 영향을 조사하였다. 광촉매 코팅된 nonporous glass bead 담체와 porous silica-based 담체를 각각 광촉매반응기에 충전하였을 때에 반사필름이 부착된 개선된 광촉매반응기 외경에서 측정한 광도는, 반사필름이 부착되지 않아서 광도가 제고되지 않은 광촉매반응기보다 각각 30.1%와 28.5% 증가하였다. Porous silica-based 담체를 충전한 개선된 광촉매반응기의 제거효율에 대한 제고효과는 약 2~3%이었다. 그러나 glass-bead 담체를 충전했을 때에 개선된 광촉매반응기의 제거효율 제고효과는 미미하였다. Porous silica-based 담체가 충전된 개선된 광촉매반응기인 최적화 광촉매반응기의 경우의 황화수소 및 톨루엔 제거효율은 nonporous glass bead가 충전되고 반사막이 없는 광촉매반응기 경우의 제거효율인 각각 19%와 53%보다 각각 약 26%와 약 60%의 증가율을 보였다. 반사막 필름표면의 roughness가 종래의 상업용 거울의 roughness보다 4배 정도 컸으나, 향후 개선된 광촉매반응기의 반사막의 roughness를 개선할 경우에 광도 개선효과가 더욱 커져서 이에 따른 악취 및 VOC를 함유한 광촉매 처리효율이 더욱 제고되리라 예상된다.

• 한국환경과학회지
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• 제24권3호
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• pp.317-322
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• 2015

The photocatalytic decomposition characteristics of toluene, acetone, and methyl mercaptan (MM) by UV reactor installed with $TiO_2$-coated perforated plane were studied. The removal efficiency of single toluene, acetone, and MM vapor was increased with increasing oxygen concentration, but decreased with increasing inlet concentration. Elimination capacity of single toluene, acetone, and MM vapor was obtained to be $628g/m^3{\cdot}day$, $1,041g/m^3{\cdot}day$, and $2,158g/m^3{\cdot}day$, respectively. Also, the photocatalytic decomposition of binary vapor consisted of toluene and acetone, toluene and MM, acetone and MM were observed. Elimination capacity of toluene mixed with acetone, toluene mixed with MM, acetone mixed with toluene, acetone mixed with MM, MM mixed with toluene, and MM mixed with acetone was $327g/m^3{\cdot}day$, $512g/m^3{\cdot}day$, $128g/m^3{\cdot}day$, $266g/m^3{\cdot}day$, $785g/m^3{\cdot}day$ and $883g/m^3{\cdot}day$, respectively. The inhibitory effect of acetone was higher than MM in photocatalytic decomposition of toluene, the inhibitory effect of toluene was higher than MM photocatalytic decomposition of acetone, and the inhibitory effect of toluene was higher than acetone in photocatalytic decomposition of MM.

• 한국환경과학회지
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• 제23권12호
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• pp.1971-1976
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• 2014

In this study, the photocatalytic decomposition characteristics of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed methyl mercaptan (MM) by UV reactor installed with $TiO_2$-coated perforated plate were studied. The photocatalytic decomposition rate of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed with MM fitted well on Langmuir-Hinshelwood (L-H) kinetics equation. The maximum elimination capacity was obtained to be $628g/m^3{\cdot}d$ for single toluene, $499g/m^3{\cdot}d$ for toluene mixed with benzene, $318g/m^3{\cdot}d$ for toluene mixed with acetone, and $513g/m^3{\cdot}d$ for toluene mixed with MM, respectively. The negative effect in photocatalytic decomposition of toluene are found to be in the order of acetone>benzene>MM.