• 산업기술연구
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• 제17권
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• pp.249-254
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• 1997

Photocatalytic reaction using $TiO_2$ thin film was applied for the inactivation of coliform bacteria and the degradation of formic acid. UV processes coupled with and without $TiO_2$ were tested for the river water samples. It took 5 and 15 minutes, respectively, to obtain 99% destruction of coliform bacteria in the total coliform test, which demonstrated the effectiveness of the photocatalytic reaction. Complete degradation of formic acid determined by TOC analysis was observed in 20 minutes by ozone/photocatalysis, while formic acid was degraded as little as about 20% during the first 100 minutes by ozone treatment alone. When ozone was supplied to the $TiO_2/UV$ system, however, it provided a synergetic effect for the degradation of formic acid.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.85-86
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• 2003

Shrink-proofing processing of wool fabrics is practically carried out by means of oxidation of wool with choline and/or covering of wool surface with resins. But, these are not necessarily environmentally friendly process causing a waste fluid containing organic chlorine compounds. Development of alternative method using more environmentally friendly process is desired. In this study, utilization of titanium oxide, TiO$_2$, photocatalytic reaction for the shrink-proofing of wool has been examined. It was found that the treatment of wool by TiO$_2$ photocatalytic reaction gave good shrink-proofing characteristics to wool fabrics.

• 상하수도학회지
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• 제12권1호
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• pp.88-95
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• 1998

The Electron/Hole Pair is generated when the Activation Energy produces by Ultraviolet Ray illumination to the Semiconductor. And $OH^-$ ion produces by Water Photo-Cleavage reacts with Positive Hole. As a result, OH Radical acting as strong oxidant is generated and then Photocatalytic Oxidation Reaction occurs. The Photocatalytic Oxidation can oxidize the chlorophenol to Chloride and Carbon Dioxide easier, safer and shorter than conventional Water Treatment Process With the same degree of chlorination, the $Cl^-$ ion at para (C4) position is most easily replaced by the OH radical. And then, the blocking effect of $OH^-$ ion between the $Cl^-$ ions and $Cl^-$ ions at symmetrical location is easily replaced by the OH radical. For mono-, di-, tri-chlorophenols, there is no obvious difference in decomposition rate, decomposition efficiency and completeness of the decomposition reaction except for 2,3-dichloropheno, 2,4,5-, 2,3,4-trichlorophenol. The decomposition efficiency is higher than 75% and completeness of the decomposition reaction is higher than 70%. Therefore, continuous flow photocatalytic reactor is promising process to remove the chlorinated aromatic compounds which is more toxic than non-chlorinated aromatic compound.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1110-1116
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• 2014

The cuprous oxide cubes with the special porous surface constructed by nano-prisms have been successfully fabricated by a solvothermal method. The template-free method is simple and facile without any surfactant. The X-ray powder diffraction (XRD) pattern suggests that the as-prepared product is the pure primitive cubic $Cu_2O$. The effects of the experimental parameters, such as the reaction temperature, reaction time and the concentration of sodium acetate anhydrous, on the morphologies of the products were investigated in detail by the scanning electron microscopy (SEM). Based on the time-dependent experiments, the possible formation mechanism was proposed. Using photocatalytic degrading reactive dyes as the model reaction and xenon lamp to simulate sunlight, the $Cu_2O$ cubes with the porous surface might possess higher photocatalytic activity than those of the commercial $Cu_2O$ powder in the visible-light region, indicating the excellent photocatalytic performance.

• 한국산학기술학회논문지
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• 제14권3호
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• pp.1527-1532
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• 2013

본 휘발성유기화합물인 아세트알데하이드와 MEK(methylethylketone)의 광촉매분해특성을 회분식 광반응기를 이용하여 연구하였다. 광촉매분해반응의 주요 반응변수인 아세트알데하이드와 MEK의 초기농도, 수분함량, 그리고 반응온도의 영향을 조사하였다. 아세트알데하이드와 MEK의 광촉매 분해속도에서 어느 일정농도까지는 초기농도가 증가할수록 증가하나, 그 이상에서는 완만한 증가형태를 보이며, 분해반응형태는 Langmuir-Hinselwood 모델이었다. 아세트알데하이드와 MEK의 광분해반응에 있어 수분은 inhibitor 역할을 수행하였다. 그리고 아세트알데하이드와 MEK 분해반응에 있어 최적의 반응온도는 $45^{\circ}C$이었다.

• 청정기술
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• 제26권4호
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• pp.311-320
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• 2020

본 연구에서는 단순 침전법으로 제조한 CdS 및 CdZnS/ZnO 광촉매를 이용하여 가시광선하에서 로다민 B, 메틸 오렌지 및 메틸렌 블루 등에 대한 광분해 반응 연구를 수행하였다. 특히 염료와 광촉매의 물리화학적 성질이 전체 광촉매 반응의 반응 경로에 미치는 영향에 대해 중점을 두고 검토하였다. X선 회절분석법, UV-vis 확산반사 분광법 그리고 X선 광전자 분광분석법 등을 이용하여 제조된 촉매들의 물리화학적 특성을 분석하였다. CdS 및 CdZnS/ZnO 광촉매 모두 자외선뿐만 아니라 가시광선 영역에 있어서도 우수한 광흡수 특성을 나타내었다. 메틸 오렌지의 경우에는 CdS 및 CdZnS/ZnO 각각의 광촉매 상에서 동일한 반응기구를 통해 반응이 진행되는 반면, 로다민 B 및 메틸렌 블루는 각각의 광촉매 상에서 서로 다른 반응 경로를 통해 광분해 반응이 진행되는 것으로 나타났다. 특히 메틸렌 블루의 광분해 반응을 보면, CdZnS/ZnO 광촉매 상에서는 주로 단일분자 형태로 전체 반응이 진행되지만, CdS 상에서는 반응 초기부터 이량체를 형성하였다. 이와 같은 결과들은 CdS 및 CdZnS/ZnO 각각의 반도체 광촉매들의 전도대의 띠끝 전위 차이와 염료들의 흡착 특성 차이에 기인한 것으로 판단된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.425-425
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• 2011

The photocatalytic decomposition of toluene gas was investigated with $TiO_2$ on nano-diamond powder (NDP) under UV irradiation. Atomic layer deposition (ALD) was used for the growth of $TiO_2$ on the NDP. The structure and surface properties of catalysts were characterized by X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The photocatalytic activity for the toluene decomposition was evaluated by measuring the concentration change of toluene and $CO_2$ gas with gas chromatography (GC)-flame ionization detector (FID) system. The photocatalytic activities of $TiO_2$/NDP catalysts were compared with that of P-25. The rate of initial photocatalytic decomposition of toluene for the $TiO_2$/NDP catalysts was relatively lower when compared to P-25. The photocatalytic activity of P-25 was rapidly decreased with time, whereas, the deactivation of $TiO_2$/NDP catalysts was less pronounced. Therefore, as the reaction time increased, the photocatalytic activity of $TiO_2$/NDP catalysts became higher than that of P-25. The intermediates such as benzaldehyde or benzoic acid, etc were more easily adhered to the active site on the P-25 surface during reaction, resulting in easier deactivation of P-25. These results could be confirmed using FT-IR spectroscopy. We suggest that the NDP used as substrate can reduce the deactivation of $TiO_2$ on the surface.

• Advances in environmental research
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• 제4권1호
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• pp.25-38
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• 2015

Wastewaters of textile industry cause high volume colour and harmful substance pollutions. Photocatalytic degradation is a method which gives opportunity of reduction of organic pollutants such as dye containing wastewaters. In this study, photocatalytic degradation of C.I. Basic Yellow 28 (BY28) as a model dye contaminant was carried out using Degussa P25 in a photocatalytic reactor. The experiments were followed out at three different azo dye concentrations in a reactor equipped UV-A lamp (365 nm) as a light source. Azo dye removal efficiencies were examined with total organic carbon and UV-vis measurements. As a result of experiments, maximum degradation efficiency was obtained as 100% at BY28 concentration of $50mgL^{-1}$ for the reaction time of 2.5 h. The photodegradation of BY28 was described by a pseudo-first-order kinetic model modified with the langmuir-Hinshelwood mechanism. The adsorption equilibrium constant and the rate constant of the surface reaction were calculated as $K_{dye}=6.689{\cdot}10^{-2}L\;mg^{-1}$ and $k_c=0.599mg\;L^{-1}min^{-1}$, respectively.

• 동력기계공학회지
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• 제18권6호
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• pp.133-139
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• 2014

In this research, the photocatalytic degradation of benzothiophene in $TiO_2$ aqueous suspension has been studied. $TiO_2$ photocatalysts are prepared by a sol-gel method. The dominant anatase-structure on $TiO_2$ particles is observed after calcining the $TiO_2$ gel at $500^{\circ}C$ for 1hr. Photocatalysts with various transition metals (Nd, Pd and Pt) loading are tested to evaluate the effect of transition metal impurities on photodegradation. The photocatalytic degradation in most cases follows first-order kinetics. The maximum photodegradation efficiency is obtained with $TiO_2$ dosage of 0.4g/L. The photodegradation efficiency with Pt-$TiO_2$ is higher than pure $TiO_2$ powder. The optimal content value of Pt is 0.5wt.%. Also we investigate the applicability of $H_2O_2$ to increase the efficiency of the $TiO_2$ photocatalytic degradation of benzothiophene. The optimal concentration of $H_2O_2$ is 0.05. The effect of pH is investigated; we obtain the maximum photodegradation efficiency at pH 9. Hydroxy-benzothiophenes and dihydroxy-benzothiophenes are identified as reaction intermediates. It is proposed that benzothiophene is oxidized by OH radical to sequentially form hydroxyl-benzothiophenes, dihydroxybenzothiophenes, and benzothiophenedione.

• 한국환경과학회지
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• 제17권7호
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• pp.801-808
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• 2008

This study was investigated experimental condition which is able to evaluate photocatalytic activity of various commercial $TiO_2$. The experiments were performed for three representative substances (ethanol, phenol and methylene blue) and four kinds of commercial $TiO_2$, under the experimental conditions such as pH, reactant concentration, amount of $TiO_2$, reaction time and UV intensity. The optimum experimental conditions to evaluate photocatalytic activity were as follows : for ethanol, the initial concentration 1000 ppm, initial pH 8, $TiO_2$ loadings 0.1 wt%, and reaction time 90 minutes: for phenol, the initial concentration 200 ppm, initial pH 8, $TiO_2$ loadings 1 wt%, and reaction time 60 minutes: for methylene blue, the initial concentration 200 ppm, initial pH 4, $TiO_2$ loadings 0.5 wt%, and reaction time 30 minutes.