• 제목/요약/키워드: photocatalytic reaction

검색결과 277건 처리시간 0.023초

CPC (Compound Parabolic Collector) 내 이산화티탄을 이용한 비스페놀 A (Bisphenol A)의 분해에 관한 연구 (Study of Degradation of Bisphenol A with $TiO_2$ Powder in CPC System)

  • 황안나;임명희;박범국;김지형
    • 한국방재학회 논문집
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    • 제11권1호
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    • pp.107-112
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    • 2011
  • 본 연구는 CPC 시스템 내에서 $Tio_2$ 슬러리와 UVA 광촉매 반응을 이용한 내분비계장애물질의 하나인 Bisphenol A(BPA)의 분해와 무기화에 대한 연구이다. 실험 영향인자로는 초기농도, 촉매량, UVA 램프 파워, 온도를 고려하였고, 초기농도는 5, 10, 20 mg/L, 촉매량은 0.1, 0.5, 1.0 g/L, UV 램프는 40, 80, 120 W, 온도는 10, 20, 30 로 조절하여 실험하였다. 초기농도 가 5 mg/L일 때 BPA는 반응시간 10분에서 80%이상이 분해되었고, 1시간 이후 10 mg/L에서는 97%, 20 mg/L에서는 49%가 분해되었다. $Tio_2$ 주입량이 0.1, 0.5 g/L일 때 BPA 분해는 비슷한 경향을 보였으며, 1시간 이후 약 70%가 분해되었으며, 1 g/L에서는 30분 이후에는 80%이상이 분해되었다. 이것은 촉매량이 증가할수록 오염물질과 반응하는 활성점이 증가하여, 광촉 매 반응 또한 증가하기 때문이라 판단된다. UV 램프가 120W일 때 반응시간 10분에서 BPA는 약 60% 이상 급격히 분해 되었다. 온도에 따른 분해정도를 알아보기 위해 온도를 조절하며 수행하였고, 온도에 따른 영향은 크지 않았다. 10 에서는 1시간 이후 46% 분해되었으며, 20에서 67%, 30에서는 69% 분해되었다.

Sulfamethoxazole의 오존산화처리에 관한 연구 (A Study on Ozonation of Sulfamethoxazole)

  • 이철규
    • 한국물환경학회지
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    • 제35권6호
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    • pp.459-469
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    • 2019
  • The ozonation of sulfamethoxazole (SMX) was performed at 20℃ using a pilot scale countercurrent bubble column reactor. Ozonation systems were combined with UV irradiation and TiO2 addition. As the oxidation reaction proceeded in each treatment system, the pH of the sample decreased and in the O3/UV/TiO2 system, the pH change was the largest from 4.54 to 2.02. Under these experimental conditions, the scavenger impact of carbonate is negligible. The highest COD and TOC removal rate was observed in the O3/UV/TiO2 system due to the UV irradiation and the photocatalytic effect of TiO2. Also, the highest mineralization ratio(ε) value is 0.2 in the O3/UV/TiO2 system, which means theoxidation capacity of the systems. The highest SMX degradation rate constants calculated by COD and TOC values (COD and TOC) were 2.15 × 10-4 sec-1 and 1.00 × 10-4 sec-1 in the O3/UV/TiO2 system, respectively. The activation energy (Ea) of ozone treatment follows the Arrhenius law. It was calculated based on COD and TOC. Each activation energy decreased in order of single O3> O3/TiO2> O3/UV > O3/UV/TiO2 system. The result showed that ΔH is more effective than ΔS in each SMX ozontaionsystem, that is characteristic of the common oxidation reaction.

광전기촉매 공정과 전기/UV 공정을 이용한 Rhodamine B의 색 제거 (Decolorization of a Rhodamine B Using Photoelectrocatalytic and Electrolytic/UV Process)

  • 김동석;박영식
    • 한국환경과학회지
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    • 제17권9호
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    • pp.1023-1032
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    • 2008
  • The feasibility study of the application of the photoelectrocatalytic and electrolytic/UV decolorization of Rhodamine B (RhB) was investigated in the photoelectrocatalytic and electrolytic/UV process with $TiO_2$ photoelectrode and DSA (dimensionally stable anode) electrode. Three types of $TiO_2$ photoelectrode were used. Thermal oxidation electrode (Th-$TiO_2$) was made by oxidation of titanium metal sheet; sol-gel electrode (5G-$TiO_2$) and powder electrode (P-$TiO_2$) were made by coating and then heating a layer of titania sol-gel and slurry $TiO_2$ on titanium sheet. DSA electrodes were Ti and Ru/Ti electrode. The relative performance for RhB decolorization of each of the photoelecoodes and DSA electrodes is: Ru/Ti > Ti > SG-$TiO_2$ > Th-$TiO_2$. It was observed that photoelectrocatalytic decolorization of RhB is similar to the sum of the photocatalytic and electrolytic decolorization. Therefore the synergetic effect was not showed in pthotoelectrocatalytic reaction. $Na_{2}SO_{4}$ and NaCl showed different decolorization effect between pthotoelectrocatalytic and electrolytic/UV reaction. In the presence of the NaCl, RhB decolorization of Ru/Ti DSA electrode was higher than that of the other photoelectrode and Ti electrode. Optimum current, NaCl dosage and UV lamp power of the electrolytic/UV process (using Ru/Ti electrode) were 0.75 A, 0.5 g/L and 16 W, respectively.

기-액 복합 광반응기에서의 악취성 암모니아 제거를 위한 촉매개발과 반응시스템의 최적조건 색출 연구 (The Studies of Photocatalyst Development and the Optimum Operation Conditions for the Removal of Ammonia in a Mixed Reactor of Liquid-vapor Phase)

  • 김해리;전민규;김준우;주광태;정석진
    • 한국대기환경학회지
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    • 제24권5호
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    • pp.512-522
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    • 2008
  • Ammonia is a major compound of odor in livestock house. To enhance the performance of ammonia oxidation (decomposition). the gas-liquid, two phase photocatalytic oxidation system was designed and prepared in this study. Commercial P-25 as $TiO_2$ catalyst was used for ammonia decomposition. V/P-25 catalyst prepared by sol gel method was also used for the removal of by-producted $NO_x$ in $NH_3$ oxidation reaction. When $TiO_2$ was used as a photocatalyst, the conversion to $N_2$ in ammonia decomposition reached above 90% until 200hr (The air flow rate of 4L/min with the ammonia concentration up to 25ppm.). However, considerable amounts of NO and $NO_2$ were formed as a result of $NH_3$ oxidation (as a by-product). Therefore, we added Vanadia impregnated $TiO_2$(P-25) catalyst for the removal of $NO_x$ at the end of reaction trail. The results of a pilot-scale operation were successful to achieve the simultaneous removal of $NH_3\;and\;NO_x$ about 81 and 87%, respectively.

Ag2Se-Graphene/TiO2 Nanocomposites, Sonochemical Synthesis and Enhanced Photocatalytic Properties Under Visible Light

  • Meng, Ze-Da;Zhu, Lei;Ghosh, Trisha;Park, Chong-Yeon;Ullah, Kefayat;Nikam, Vikram;Oh, Won-Chun
    • Bulletin of the Korean Chemical Society
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    • 제33권11호
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    • pp.3761-3766
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    • 2012
  • $Ag_2Se$-Graphene/$TiO_2$ composite was synthesized by a facile sonochemical method. The as-prepared products were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectrophotometer. During the reaction, both of the reduction of graphene oxide and loading of $Ag_2Se$ and $TiO_2$ particles were achieved. The as-prepared $Ag_2Se$-Graphene/$TiO_2$ composites possessed great adsorptivity of dyes, extended light absorption range, and efficient charge separation properties simultaneously. Hence, in the photodegradation of rhodamine B (Rh.B), a significant enhancement in the reaction rate was observed with $Ag_2Se$-Graphene/$TiO_2$ composites, compared to the pure $TiO_2$. The high activity can be attributed to the synergetic effects of high charge mobility, and red shift in absorption edge of $Ag_2Se$-Graphene/$TiO_2$ composites.

TiO2 나노분말과 수산화알칼리와의 반응으로부터 티탄산 나노튜브의 형성과 나노구조의 전개 (Titanate Nanotube Formation and Nanostructure Development from the Reaction of TiO2 Nanopowder and Alkalihydroxide)

  • 진은주;류도형;허승헌;김창열;황해진
    • 한국분말재료학회지
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    • 제15권2호
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    • pp.125-135
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    • 2008
  • [ $TiO_2$ ] nanotubes for photocatalytic application have been synthesized by hydrothermal method. $TiO_2$ nanotubes are formed by washing process after reaction in alkalic solution. Nanotubes with different morphology have been fabricated by changing NaOH concentration, temperature and time. $TiO_2$ nanoparticles were treated inside NaOH aqueous solution in a Teflon vessel at $110^{\circ}C$ for 20 h, after which they were washed with HCl aqueous solution and deionized water. Nanotube with the most perfect morphology was formed from 0.1 N HCl washing treatment. $TiO_2$ nanotube was also obtained when the precursor was washed with other washing solutions such as $NH_4OH$, NaCl, $K_2SO_4$, and $Na_2SO_3$. Therefore, it was suggested that $Na^+$ ion combined inside the precursor compound slowly comes out from the structure, leaving nanosheet morphology of $TiO_2$ compounds, which in turn become the nanotube in the presence of hydroxyl ion. To stabilize the sheet morphology, the different type of washing treatment solution might be considered such as amine class compounds.

회분식 반응기에서 TiO2 광촉매의 MEK 분해특성-금속담지영향 (Characteristics of MEK Degradation using TiO2 Photocatalyst in the Batch-type Reactor-Metal Doping Effect)

  • 장현태;차왕석
    • 한국산학기술학회논문지
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    • 제16권2호
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    • pp.1579-1584
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    • 2015
  • 광촉매반응에서 티타니아에 금속물질을 담지하면 광촉매표면이 변화되며 담지된 금속물질은 반응속도를 증가시킨다. 회분식 광반응기를 이용하여 $TiO_2$ 광촉매에 대한 금속물질 담지와 담지된 촉매의 소성조건 영향을 조사하였다. 광분해 효율을 증진시키기 위해 $TiO_2$ 촉매에 여러 종류의 금속물질을 담지하였다. 모든 실험에서의 수분함량은 3wt%, 반응기 온도는 $40^{\circ}C$이었다. $TiO_2$에 팔라듐을 담지한 경우가 가장 우수하였으며, Pt와 W을 첨가한 경우도 양호하였다. Pd/$TiO_2$ 촉매에 백금 또는 텅스텐을 부가적으로 담지하여도 제거효율에서의 증가는 없었다. 적절한 소성조건을 얻기위해 소성온도와 소성시간에 대하여 다양하게 실험을 수행하였으며, 실험결과 최적의 소성조건은 소성온도 $400^{\circ}C$, 소성시간 1시간이었다.

Pd/r-TiO2 나노튜브 이종결합 광촉매의 합성과 특성 (Synthesis and Characteristics of Pd/r-TiO2 Nanotube Arrays Hetrojunction Photocatalyst)

  • 이종호;이영기;김영직;장경욱;오한준
    • 한국재료학회지
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    • 제32권1호
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    • pp.14-22
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    • 2022
  • To improve light absorption ability in the visible light region and the efficiency of the charge transfer reaction, Pd nanoparticles decorated with reduced TiO2 nanotube photocatalyst were synthesized. The reduced TiO2 nanotube photocatalyst was fabricated by anodic oxidation of Ti plate, followed by an electrochemical reduction process using applied cathodic potential. For TiO2 photocatalyst electrochemically reduced using an applied voltage of -1.3 V for 10 min, 38% of Ti4+ ions on TiO2 surface were converted to Ti3+ ion. The formation of Ti3+ species leads to the decrease in the band gap energy, resulting in an increase in the light absorption ability in the visible range. To obtain better photocatalytic efficiency, Pd nanoparticles were decorated through photoreduction process on the surface of reduced TiO2 nanotube photocatalyst (r10-TNT). The Pd nanoparticles decorated with reduced TiO2 nanotube photocatalyst exhibited enhanced photocurrent response, and high efficiency and rate constant for aniline blue degradation; these were ascribed to the synergistic effect of the new electronic state of the TiO2 band gap energy induced by formation of Ti3+ species on TiO2, and by improvement of the charge transfer reaction.

이산화티탄 광촉매 환기장치의 오염물질 저감 실험 (Experiment on Reduction of Pollutants in Titanium Dioxide Photocatalytic Ventilation System)

  • 송용우
    • 토지주택연구
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    • 제13권2호
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    • pp.117-123
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    • 2022
  • 본 연구는 대표적인 미세먼지와 실내유해물질인 질소산화물의 저감을 위해 이산화티탄 광촉매를 환기장치에 적용한 것으로 그 내용은 다음과 같다. 기존 연구는 실내에 자외선 적용의 한계로 인해 주로 건축자재에 광촉매 혼입을 통해 실외 자재를 대상으로 진행되었다. 자외선 실내 적용 한계를 극복하고자 기존 선행연구를 통해 확인된 이산화티탄 광촉매의 오염물질 분해 효과를 실내에 적용이 가능하도록 자외선램프의 설치가 가능한 반응장치를 설계 및 제작하였다. 해당 반응장치를 실내 환기장치에 적용하여 Mock-Up에 적용하였다. Mock-Up 실험은 그 체적을 시간당 1회, 5회 환기하는 풍량을 변화시켜 NOx 저감 성능을 확인하였다. 그 결과, 환기 풍량이 증가함에 따라 NOx 저감시간이 비례하여 감소되어 그 성능이 증가하는 것을 확인하였다. 해당 연구를 통해 오염물질 저감 효과를 가진 이산화티탄 광촉매의 실내 활용 방안과 그 성능을 확인할 수 있는 기초적인 연구 결과를 도출하였다.

Synthesis and characterization Au doped TiO2 film for photocatalytic function

  • Son, Jeong-Hun;Bae, Byung-Seo;Bae, Dong-Sik
    • 한국결정성장학회지
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    • 제25권6호
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    • pp.280-284
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    • 2015
  • Au doped $TiO_2$ nanoparticles have been synthesized using a reverse micelle technique combined with metal alkoxide hydrolysis and condensation. Au doped $TiO_2$ was coated with glass substrate. The size of the particles and thickness of the coating can be controlled by manipulating the relative rates of the hydrolysis and condensation reaction of TTIP within the micro-emulsion. The average size of synthesized Au doped $TiO_2$ nanoparticle was about in the size range of 15 to 25 nm and the Au particles formed mainly the range of 2 to 10 nm in diameter. The effect of synthesis parameters, such as the molar ratio of water to TTIP and the molar ratio of water to surfactant, are discussed. The synthesized nanopaticles were coated on glass substrate by a spin coating process. The thickness of thin film was about 80 nm. The degradation of MB on a $TiO_2$ thin film was enhanced over 20 % efficiency by the incorporation of Au.