• Title/Summary/Keyword: Photocatalytic Degradation

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플라스틱 광섬유 광촉매 반응기에서 태양에너지를 이용한 TCE의 광촉매 분해 (Photocatalytic degradation of TCE using solar energy in POFR)

  • 정희록;문일;주현규;전명석
    • 한국태양에너지학회 논문집
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    • 제22권3호
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    • pp.57-65
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    • 2002
  • The photocatalytic degradation of TCE using solar energy in POFR was studied. The use of solar energy was investigated in plastic optica fiber photocatalytic reactor (POFR). In POFR, the main parameters of photocatalytic degradation of TCE were lihgt intensity, thickness of $TiO_2$-coated film on plastic fiber core, the same of total $TiO_2$-coated surface area with changed length. We studied the apparent photonic efficiency and photocatalytic degradation rate of TCE in POFR. The apparent photonic efficiency of various light intensities was decreased by an incresed intensities. The photocatalytic activities of $TiO_2$-coated optical fiber reactor system depended on the coating thickness, and total clad-stripped surface area of POF. Photocatalytic degradation of trichloroethylene ($C_2HCl_3$, TCE) in the gas-phase was elucidated by using $TiO_2$-coated plastic optical fiber reactor. In TCE degradation, in-situ FTIR measurement resulted in mineralization into $CO_2$.

Sequential microbial-photocatalytic degradation of imidacloprid

  • Sharma, Teena;Kaur, Manpreet;Sobti, Amit;Rajor, Anita;Toor, Amrit Pal
    • Environmental Engineering Research
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    • 제25권4호
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    • pp.597-604
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    • 2020
  • In the present study, the application of sequential biological and photocatalytic process was evaluated as a feasible process for the degradation of imidacloprid (IMI) in soil. Photocatalysis was carried out as a post and pre-treatment to the biological process as Microbial Photocatalytic (MP) and Photocatalytic Microbial (PM), respectively, to enhance the degradation and mineralization of IMI in soil. By both the processes, there was an enhancement in the percentage degradation of IMI i.e 86.2% for PM and 94.6% for MP process. The obtained results indicate that MP process is apparently more efficient in degradation of IMI which was observed with 15 days of biological treatment followed by 18 h of photocatalytic degradation (15 d + 18 h). The present work also reveals that though the difference in terms of the degradation of IMI after 5 d + 18 h, 10 d + 18 h & 15 d+ 18 h of MP process is not drastic, yet significant variation has been observed in terms of mineralization that truly signifies the removal of IMI from the soil. The LC analysis has shown that the intermediates formed during MP process are more and smaller in comparison to PM process, which further provides evidence that MP process is better than PM process for effective degradation of IMI in soil.

Degradation of Volatile Hydrocarbons Using Continuous-Flow Photocatalytic Systems with Enhanced Catalytic Surface Areas

  • Jo, Wan-Kuen;Yang, Sung-Hoon;Shin, Seung-Ho;Yang, Sung-Bong
    • Environmental Engineering Research
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    • 제16권2호
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    • pp.91-96
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    • 2011
  • Limited information is available on the degradation of volatile hydrocarbons determined via the use of plate-inserted photocatalytic reactors. This has led to the evaluation of surface areas of cylindrical continuous-flow photocatalytic reactors for the degradation of three selected aromatic hydrocarbons. Three types of reactors were prepared: a double cylinder-type, a single cylindrical-type without plates and a single cylindrical-type with inserted glass tubes. According to diffuse reflectance, FTIR and X-ray diffraction (XRD) spectroscopy, the surface characteristics of a coated photocatalyst were very similar to those of raw $TiO_2$, thereby suggesting that the coated photocatalyst exhibited the same photocatalytic activity as the raw $TiO_2$. The photocatalytic degradation efficiencies were significantly or slightly higher for the single cylinder-type reactor than for the double cylinder-type reactor which had a greater catalytic surface area. However, for all target compounds, the degradation efficiencies increased gradually when the number of plates was increased. Accordingly, it was suggested that the surface area being enhanced for the plate-inserted reactor would elevate the photocatalytic degradation efficiency effectively. In addition, this study confirmed that both initial concentrations of target compounds and flow rates were important parameters for the photocatalytic removal mechanism of these plate-inserted photocatalytic reactors.

Effects of Water Vapor, Molecular Oxygen and Temperature on the Photocatalytic Degradation of Gas-Phase VOCs using $TiO_2$Photocatalyst: TCE and Acetone

  • Kim, Sang-Bum;Jo, Young-Min;Cha, Wang-Seong
    • Journal of Korean Society for Atmospheric Environment
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    • 제17권E2호
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    • pp.35-42
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    • 2001
  • Recent development of photocatalytic degradation method that is mediated by TiO$_2$ is of interest in the treatment of volatile organic compounds(VOCs). In this study, trichloroethylene(TCE) and acetone were closely examined in a batch scale of photo-reactor as a function of water vapor, oxygen, and temperature. Water vapor inhibited the photocatalytic degradation of acetone, while there was an optimum concentration in TCE. A lower efficiency was found in nitrogen atmosphere than air, and the effect of oxygen on photocatalytic degradation of acetone was greater than on that of TCE. The optimum reaction temperature on photocatalytic degradation was about 45$^{\circ}C$ for both compounds. NO organic byproducts were detected for both compounds under the present experimental conditions. It was ascertained that the photocatalytic reaction in a batch scale of photo-reactor was very effective in removing VOCs such as TCE and acetone in the gaseous phase.

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TiO2현탁액에 의한 Brilliant Blue FCF의 광촉매 분해 (Photocatalytic Degradation of Brilliant Blue FCF with TiO2 Suspension)

  • 정갑섭;최수일
    • 한국환경과학회지
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    • 제13권6호
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    • pp.599-603
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    • 2004
  • In a batch reactor, the characteristics of photocatalytic degradation of brilliant blue FCF in titanium dioxide suspension was studied under the irradiation of ultra-violet ray. Photocatalytic degradation in anatase type of TiO$_2$ was more effective than in rutile type of $TiO_2$ below the dosage of 5g. The degradation rate was slightly increased with decreasing initial pH of brilliant blue FCF aqueous solution, but rapidly increased with the addition of oxidant. Potassium bromate acted as more effective oxidant than ammonium persulfate. The photocatalytic degradation rate of brilliant blue FCF was pseudo-first order with rate constants of 0.012, 0.006 and $0.003min^{-1}$ at initial pH 3.1, 5.2 and 7.1 of brilliant blue FCF solution, respectively.

A Study on Degradation of Nonylphenol Polyethoxylate Metabolites Using Uv / Photocatalytic Silicagel Treatment

  • Asano, Masahiro;Kishimoto, Naoyuki;Jiku, Fumihiko;Somiya, Isao
    • 한국습지학회지
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    • 제9권1호
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    • pp.99-105
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    • 2007
  • Nonylphenol polyetoxylates (NPnEOs) metabolites; nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), nonylphenoxyacetic acid (NPEC) (collectively referred to "NPE-c") were examined for their degradations by using of lab-scale UV/photocatalytic silicagel (ultraviolet photocatalytic degradation in the presence of silicagel coated with titanium dioxide as a catalyst) reactor. NPE-c degradations by UV/photocatalytic silicagel treatment reached approximately 85-93 % after 40 min irradiation independently of its initial concentration (between ca. 0.5 and 2.0mg/l). Any intermediates under the NPE-c degradation were not identified by GC/MS sample analysis. Degradations of NPE-c were followed pseudo first-order kinetics. Then, the effectiveness of UV/photocatalytic silicagel treatment for degradation of NPE-c was in the order of NPEC > NP > NP1EO.

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역상마이셀에 의한 나노크기 이산화티탄의 제조 및 브로메이트 광분해 특성 (A Photocatalytic Degradation of Bromate over Nanosized Titanium Dioxide Prepared by Reverse Micelle)

  • 이만식;홍성수;박홍재;정영언;박원우
    • 한국환경과학회지
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    • 제11권9호
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    • pp.987-992
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    • 2002
  • Nanosized titania sol has been produced by the controlled hydrolysis of titanium tetraisopropoxide(TTIP) in sodium bis(2-ethylhexyl)sulfosuccinate(AOT) reverse micelles. The physical properties, such as crystallite size and crystallinity according to R ratio have been investigated by FT-IR, XRD and UV-DRS. In addition, the photocatalytic degradation of bromate has been studied by using batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. It is shown that the anatase structure appears in the 300~$600^{\circ}C$ calcination temperature range and the formation of anatase into rutile starts above $700^{\circ}C$. The crystallite size increases with increasing R ratio. In the photocatalytic degradation of bromate, the photocatalytic decomposition of bromate shows the decomposition rate increases with decreasing initial concentration of bromate and with increasing intensity of light.

A Kinetic Study on the Photocatalytic Degradation of Gas-Phase VOCs Using TiO$_2$ photocatalyst

  • Kim, Sang-Bum;Jo, Young-Min;Hong, Sung-Chang
    • Journal of Korean Society for Atmospheric Environment
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    • 제17권E3호
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    • pp.117-124
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    • 2001
  • The present paper examined the kinetics of photocatalytic degradation of volatile organic compounds (VOCs) including gaseous trichloroethylene (TCE) and acetone. In this study, we examined the effects of the initial concentration of VOCs and the light intensity of ultra-violet (UV). A batch photo-reactor was specifically designed for this work. The photocatalytic degradation rate increased with the initial concentration of VOCs but remained almost constant beyond a certain concentration. It matched well with the Langmuir-Hinshelwood (L-H) kinetic model. When the effect of light intensity was concerned, it was found that photocatalytic degradation occurs in two regimes with respect to light intensity.

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순환회분식 광촉매시스템의 영향인자 연구: 광촉매 주입량, 용존산소, 체류시간,전자포획 첨가금속 (Factors influencing a Photocatalytic System in Circulating Batch Mode: Photocatalyst Dosage, DO, Retention Time and Metal Impurities)

  • 김일규
    • 상하수도학회지
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    • 제27권1호
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    • pp.49-58
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    • 2013
  • A selected halogenated organic contaminant, monochlorophenol was successfully degraded by photocatalytic reaction in a circulating batch system. The photocatalytic degradation in most cases follows first-order kinetics. The photocatalytic reaction rate increased in the $TiO_2$ dosage range of 0.1 g/L to 0.4 g/L, then decreased with further increase of the dosage. Also the degradation rate increased over the range of the retention time from 0.49 min. to 0.94 min., then decreased with further increase of the retention time in the circulating batch reactor. The photocatalytic activity was enhanced by addition of metal impurities, platinum(Pt) and palladium(Pd) onto the photocatalysts. The photocatalytic degradation rate increased with the increase of Pt and Pd in the content range of 0 to 2wt %, then decreased with further increase of the metal contents. Therefore the metal loading to $TiO_2$ influence the degradation rate of a halogenated organic compound by acting as electron traps, consequently reducing the electron/positive hole pair recombination rate.

산화아연 현탁액에 의한 타르색소의 광분해 (Photodecomposition of Tar Colorant With Zinc Oxide Suspension)

  • 정갑섭
    • 한국환경과학회지
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    • 제15권12호
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    • pp.1155-1161
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    • 2006
  • The characteristics of photocatalytic degradation of tar colorants such as brilliant blue FCF(BBF) and tartrazine(TTZ) with zinc oxide suspension was studied in a batch reactor under irradiation of ultra-violet ray. Photocatalytic degradation of TTZ with ZnO was more higher than that of BBF, and was Increased with dosage of ZnO below 5g, but was nearly affected with initial pH of two tar colorants aqueous solution. Ammonium persulfate was more effective oxidant than potassium bromate which slightly increased the degradation of BBF, but not increased the degradation of TTZ. The photocatalytic degradation rates of BBF and TTZ were pseudo-first order with rate constants of 0.0066, 0.0092 and $0.015min^{-1}$ for BBF, 0.042, 0.017 and $0.110min^{-1}$ for TTZ at the dosage of 1, 2 and 5g ZnO, respectively.