• 제목/요약/키워드: Visible-light irradiation

검색결과 225건 처리시간 0.022초

Degradation and mineralization of violet-3B dye using C-N-codoped TiO2 photocatalyst

  • Putri, Reza Audina;Safni, Safni;Jamarun, Novesar;Septiani, Upita;Kim, Moon-Kyung;Zoh, Kyung-Duk
    • Environmental Engineering Research
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    • 제25권4호
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    • pp.529-535
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    • 2020
  • The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO2 catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO2 followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L-1 violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO2 catalyst, and approximately 44% TOC was removed as a result of the mineralization.

주사슬에 말로네이트기를 가지는 신규 폴리에스테르의 합성과 광분해 특성을 이용한 형광 이미지 패터닝 (Synthesis of Novel Network Polyesters Containing Malonate Group in Main Chain and Their Fluorescence Image Patterning via Photodegradation)

  • 정선주;곽기섭;정인태;이동호;노형진;윤근병
    • 폴리머
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    • 제32권1호
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    • pp.56-62
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    • 2008
  • Diol과 diacid 단량체들의 다양한 조합으로 2단계 축합중합으로 가교구조를 가지는 세 종류의 신규 폴리에스테르를 새롭게 합성하였다. 이들 고분자 필름은 $240^{\circ}C$에서 수 시간 고온 열처리하면, 주사슬에 의한 금지 전이에도 불구하고, 가시영역에서 흡수를 나타내었으며 330 nm 이상의 파장에서 여기시키면 청색에서 근적외선에 이르는 넓은 범위에서 발광을 나타내었다. 신규 폴리에스테르의 발광 현상은 주사슬에 포함된 말로네이트기가 고온 열처리를 통해 자기축합 형태의 Knoevenagel 반응을 일으켜 분자 내 공역구조를 형성하기 때문이다. 또한 이들 고분자의 열적 특성은 가지화도 차이에 의한 화학적 가교정도에 따라 현저한 차이를 보였을 뿐 아니라 광분해 현상도 관찰되었다. 필름 상태에서 강한 자외선을 조사하여 말로네이트기의 분해반응을 유도하고, 이를 이용한 형광 이미지 패터닝을 수행한 결과, 고해상도의 이미지 패턴을 얻을 수 있었다.

B, C, N, F 원소 다중도핑된 TiO2의 가시광 광촉매 분해 반응 (Photo-catalytic Degradation on B-, C-, N-, and F Element co-doped TiO2 under Visible-light Irradiation)

  • 배병철;임지선;김종구;이영석
    • 공업화학
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    • 제21권1호
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    • pp.29-33
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    • 2010
  • 본 연구에서는 여러 가지 열처리 온도에서 다성분 도핑에 의한 광촉매의 밴드갭 저감 및 가시광 광분해 효과를 알아보고자 tetraethylammonium tetrafluoroborate (TEATFB)로 B, C, N, F 등이 동시에 도핑된 $TiO_{2}$ 광촉매를 제조하였다. 도핑된 $TiO_{2}$ 광촉매가 가시광선영역에서 분해되는 정도를 확인하기 위해서 태양광에 조사하여 rhodamine B와 acridine orange로 염료분해 실험을 수행하였다. XRD 결과 $800^{\circ}C$ 이하에서 열처리된 $TiO_{2}$ 광촉매는 anatase 구조가 존재하고 있음을 알 수 있었다. XPS 분석을 통하여 광활성에 영향을 미치는 B, C, N, F의 결합구조를 확인하였고 UV-DRS 결과로부터 다성분 도핑된 $TiO_{2}$ 광촉매의 밴드 갭이 2.98 eV로 줄어든 것을 알 수 있었다. 다성분 도핑 $TiO_{2}$의 태양광 조사에 의한 UV-Vis 결과에서 acridine orange에 대한 광분해 효과가 도핑되지 않은 샘플에 비해 1.61배 증가함을 알 수 있었다. 특히, 다성분이 동시 도핑되고 $700^{\circ}C$에서 열처리된 샘플이 acridine orange과 rhodamine B 두 가지 염료 모두에서 가장 좋은 광분해 효과를 보여 주었다.

TiO2 광촉매를 함유한 PET와 나일론 6 나노복합체막의 자외선/오존에 대한 안정성 (The UV/Ozone Stability of PET and Nylon 6 Nanocomposite Films Containing TiO2 Photocatalysts)

  • 진성우;장진호
    • 한국염색가공학회지
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    • 제26권2호
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    • pp.88-98
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    • 2014
  • This study is to assess the photocatalytic degradation of PET and Nylon 6 films containing nano-sized $TiO_2$ powders of anatase and rutile types. The PET and Nylon 6 films containing six kinds of the nanoparticles were prepared by melt casting method using a heating press machine. Reflectance in visible region and water contact angles of the irradiated PET and Nylon 6 composite films decreased with increasing UV/$O_3$ irradiation. Also the enhanced hydrophilicity has a close relationship with the increase in the Lewis base parameter, which indicates more oxidized polymer surfaces. The photocatalytic degradation of the nanocomposite films increased with increasing $TiO_2$ content and UV energy, which is more significant with the anatase types rather than the rutile types. The amide linkages in the Nylon 6 seemed to be more susceptible to the UV light compared to the ester groups in the PET, particularly in the presence of the $TiO_2$ photocatalysts. The photoscission and photodegradation of the polymers in the composites produced more degraded structure assisted by the photocatalytic activity of the $TiO_2$ nanoparticles. Also the composite films can bleach the methylene blue dyes more easily under the UV/$O_3$ irradiation, suggesting the photobleaching activity of the $TiO_2$ nanoparticles.

Fabrication and Physicochemical Properties of Carbon/Titania/Bentonite Monolith for Architecture

  • Oh, Won-Chun;Choi, Jong-Geun;Song, Da-Ye;Kim, Ha-Rry;Chen, Ming-Liang;Zhang, Feng-Jun;Park, Tong-So
    • 한국재료학회지
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    • 제20권3호
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    • pp.167-173
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    • 2010
  • In this study, we used activated carbon (AC) and titanium oxysulfate as a titanium precursor to prepare carbon/titania composites. We then mixed it with bentonite in different ratios to make a carbon/titania/bentonite monolith for use in architecture bricks by using Phenolic rosin (PR) as a bonding agent. The physicochemical properties of the prepared composites were analyzed by BET surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), self-cleaning effect and bactericidal tests. The BET surface areas increased as the ratio of carbon/titania composites increased. The SEM microscopy showed that the $TiO_2$ and bentonite were coated on the surface of the AC. The XRD patterns showed a mixture structure of anatase and rutile of $TiO_2$ with a clear $SiO_2$ structure. The EDX spectra of the carbon/titania/bentonite monolith confirmed the presence of various elements, namely C, O, Ti and Si, as well as other, impure elements. Moreover, to determine the self-cleaning effect of the carbon/titania/bentonite monolith, we used methylene blue (MB, $C_{16}H_{18}N_3S{\cdot}Cl{\cdot}3H_2O$) in an aqueous solution under the irradiation of visible light. Accordingly, all of the samples had excellent degradation of the MB solution. Furthermore, it was observed that the composites with sunlight irradiation had a greater effect on E. coli than any other experimental conditions.

전자빔 표면 조사에 따른 SnO2/Ag/SnO2 박막의 특성 연구 (The Effect of electron beam surface irradiation on the properties of SnO2/Ag/SnO2 thin films)

  • 장진규;김현진;최재욱;이연학;공영민;허성보;김유성;김대일
    • 한국표면공학회지
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    • 제54권6호
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    • pp.302-306
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    • 2021
  • SnO2 30/Ag 15/SnO2 30 nm(SAS) tri-layer films were deposited on the glass substrates with RF and DC magnetron sputtering and then electron beam is irradiated on the surface to investigate the effect of electron bombardment on the opto-electrical performance of the films. electron beam irradiated tri-layer films at 1000 eV show a higher figure of merit of 2.72×10-3 Ω-1 than the as deposited films due to a high visible light transmittance of 72.1% and a low sheet resistance of 14.0 Ω/☐, respectively. From the observed results, it is concluded that the post-deposition electron irradiated SnO2 30/Ag 15/SnO2 30 nm tri-layer films can be used as a substitute for conventional transparent conducting oxide films in various opto-electrical applications.

가시광선하에서 황화물계 광촉매를 이용한 로다민 B의 광분해 반응기구에 대한 비교 연구 (Comparative Studies on Mechanism of Photocatalytic Degradation of Rhodamine B with Sulfide Catalysts under Visible Light Irradiation)

  • 이승현;정영재;이종민;김대성;배은지;홍성수;이근대
    • 청정기술
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    • 제25권1호
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    • pp.46-55
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    • 2019
  • CdS 및 CdZnS/ZnO를 침전법으로 제조하여 가시광선하에서의 로다민 B의 광분해 반응에 대한 광촉매로 이용하였다. 제조된 광촉매들은 X선 회절분석기와 UV-vis 확산반사 분광법 등으로 특성을 분석하였으며, 그 결과 원하는 결정구조를 지닌 광촉매들이 생성되었으며 또한 CdS 및 CdZnS/ZnO 두 가지 광촉매 모두 자외선뿐만 아니라 가시광선 영역의 빛도 효율적으로 흡수함을 알 수 있었다. 여러 종류의 활성 화학종에 대한 포집제들을 첨가하면서 각각의 광촉매에 대한 활성을 조사하였으며, 특히 두 가지 촉매상에서의 반응기구 차이점에 중점을 두고 고찰하였다. 이때 $CH_3OH$, KI 및 p-benzoquinone을 각각 ${\cdot}OH$ 라디칼, 광여기 정공 그리고 ${\cdot}O_2{^-}$ 라디칼에 대한 포집제로 이용하였다. 각각의 광촉매상에서는 서로 다른 반응기구에 의해서 반응이 진행되는 것으로 나타났다. CdS 광촉매 반응에서는 ${\cdot}O_2{^-}$ 라디칼이 그리고 CdZnS/ZnO 광촉매 반응에 있어서는 광여기 정공이 중요한 역할을 하는 것으로 판단되며, 따라서 CdS와 CdZnS/ZnO 각각의 광촉매상에서는 발색단 골격의 탈알킬화 반응 및 발색단 콘쥬케이트 구조의 절단 과정을 통하여 반응이 우선적으로 진행된다는 것을 알 수 있었다. 이러한 결과들은 CdS, CdZnS 그리고 ZnO 각각 반도체들의 전도대와 가전자대의 띠끝 전위와 활성 화학종 생성에 대한 산화환원 전위의 차이에 주로 기인한 것으로 생각된다.

Highly Crystalline 2,6,9,10-Tetrakis((4-hexylphenyl)ethynyl)anthracene for Efficient Solution-Processed Field-effect Transistors

  • Hur, Jung-A;Shin, Ji-Cheol;Lee, Tae-Wan;Kim, Kyung-Hwan;Cho, Min-Ju;Choi, Dong-Hoon
    • Bulletin of the Korean Chemical Society
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    • 제33권5호
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    • pp.1653-1658
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    • 2012
  • A new anthracene-containing conjugated molecule was synthesized through the Sonogashira coupling and reduction reactions. 1-Ethynyl-4-hexylbenzene was coupled to 2,6-bis((4-hexylphenyl) ethynyl)anthracene-9,10-dione through a reduction reaction to generate 2,6,9,10-tetrakis((4-hexylphenyl)ethynyl) anthracene. The semiconducting properties were evaluated in an organic thin film transistor (OTFT) and a single-crystal field-effect transistor (SC-FET). The OTFT showed a mobility of around 0.13 $cm^2\;V^{-1}\;s^{-1}$ ($I_{ON}/I_{OFF}$ > $10^6$), whereas the SC-FET showed a mobility of 1.00-1.35 $cm^2\;V^{-1}\;s^{-1}$, which is much higher than that of the OTFT. Owing to the high photoluminescence quantum yield of 2,6,9,10-tetrakis((4-hexylphenyl)ethynyl) anthracene, we could observe a significant increase in drain current under irradiation with visible light (${\lambda}$ = 538 nm, 12.5 ${\mu}W/cm^2$).

초음파 화학 반응을 이용한 WOx 도핑 TiO2 광촉매 나노 분말의 합성 (WOx Doped TiO2 Photocatalyst Nano Powder Produced by Sonochemistry Method)

  • 조성훈;이수완
    • 한국재료학회지
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    • 제21권2호
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    • pp.83-88
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    • 2011
  • Nano-technology is a super microscopic technology to deal with structures of 100 nm or smaller. This technology also involves the developing of $TiO_2$ materials or $TiO_2$ devices within that size. The aim of the present paper is to synthesize $WO_x$ doped nano-$TiO_2$ by the Sonochemistry method and to evaluate the effect of different percentages (0.5-5 wt%) of tungsten oxide load on $TiO_2$ in methylene blue (MB) elimination. The samples were characterized using such different techniques as X-ray diffraction (XRD), TEM, SEM, and UV-VIS absorption spectra. The photo-catalytic activity of tungsten oxide doped $TiO_2$ was evaluated through the elimination of methylene blue using UV-irradiation (315-400nm). The best result was found with 5 wt% $WO_x$ doped $TiO_2$. It has been confirmed that $WO_x-TiO_2$ could be excited by visible light (E<3.2 eV) and that the recombination rate of electrons/holes in $WO_x-TiO_2$ declined due to the existence of $WO_x$ doped in $TiO_2$.

지방산과 폴리아미드산 혼합물의 광이성질화 현상에 관한 연구 (A Study on the Photoisomerization of Fatty Acid and Polyamic Acid Mixture)

  • 박근호;박태곤
    • 한국전기전자재료학회논문지
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    • 제15권8호
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    • pp.695-701
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    • 2002
  • Maxwell displacement current (MDC) measuring technique has been applied on the study of monolayers of fatty acid and polyamic acid mixture. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about 132 $^2$and 115 $^2$just before the initial rise of the surface pressure during the 1st and 2nd mixed monolayer compressions cycle, respectively. Maxwell displacement currents were investigated in connection with mixed monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. Ultra thin film of fatty acid and polyamic acid mixture was prepared on the hydrophilic quartz plate by Langmuir-Blodgett (LB) method. The precursor LB film was heated in a vacuum dry oven at 12$0^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.