• Title, Summary, Keyword: Photocatalytic degradation

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Photocatalytic Characteristics of PbS/ZnO/TiO2 Nanotube Composite (PbS/ZnO/TiO2 나노복합체의 광촉매 특성)

  • Lee, Jong-Ho;Heo, Sujeong;Youn, Jeong-Il;Kim, Young-Jig;Kim, In-Ki;Jang, Kyung-Wook;Oh, Han-Jun
    • Korean Journal of Materials Research
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    • v.27 no.10
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    • pp.569-575
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    • 2017
  • To improve photocatalytic performance, a $PbS/ZnO/TiO_2$ nanotube catalyst was synthesized, and its surface characteristics and photocatalytic efficiency were investigated. The hybrid photocatalysts were produced by anodic oxidation and successive ionic layer adsorption and reaction(SILAR). The photocatalytic efficiency was evaluated using the dye degradation rate. The $PbS/ZnO/TiO_2$ photocatalyst significantly enhanced the photocatalytic activity for dye degradation, which was ascribed to the synergistic effect of their better absorption of solar light and a decrease in the rate of excited electron-hole recombination.

Preparation and photocatalytic activity of ACF/$TiO_2$ composites by using titanium n-butoxide and acid modified activated carbon fiber

  • Oh, Won-Chun;Kwon, Ho-Joug;Chen, Ming-Liang;Zhang, Feng-Jun;Ko, Weon-Bae
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.19 no.3
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    • pp.144-151
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    • 2009
  • Photocatalytic degradation of methylene blue (MB) in aqueous solution was investigated using $TiO_2$ coated on various acid modified activated carbon fiber (ACF). The ACFs/$TiO_2$ composites were prepared from titanium n-butoxide (TNB) as titanium precursor and various acid modified ACFs. The prepared samples are heat treated at 973 K. Then the ACF/$TiO_2$ composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX). Moreover, photocatalytic degradation of MB by the ACF/$TiO_2$ composites was determined under UV irradiation. The results shows that the photocatalytic activity of ACF/$TiO_2$ composites ($AT1{\sim}AT4$) prepared with TNB and various acid modified ACF was much better than that of ACF/$TiO_2$ composite (AT) prepared with TNB and non-acid modified ACF, and the effects improved with order of sample AT3 > AT4 > AT1 > AT2.

Degradation of MEK using continuous single module photo-catalytic reactor (연속식 광촉매반응기를 이용한 MEK 분해특성 연구)

  • Peng, Mei Mei;Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.5304-5309
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    • 2013
  • The degradation of methylethylkeone(MEK) was investigated by the continuous single module photocatalytic reactor. Operational conditions were initial concentration of MEK, intensity of photon flux, and activity change according to the long time operation. The photocatalytic degradation was decreased with the increase of MEK concentration, and the degree of decrease was larger at higher flow rate. Removal efficiency of photocatalytic reactor was decreased with the increase of reactor diameter and lamp wavelength under the same residence time condition. Continuous single module photocatalytic reactor was successfully operated without any activity drop during 120hrs operation.

Photocatalytic Degradation of Acetaldehyde and MEK using Batch Type Photo-Reactor (회분식 광촉매반응기를 이용한 아세트알데하이드와 MEK 제거특성 연구)

  • Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.3
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    • pp.1527-1532
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    • 2013
  • The kinetics of photocatalytic degradation of gaseous acetaldehyde and methylethylketone(MEK) were studied by the batch scale of photo-reactor. Variable parameters were initial concentration of acetaldehyde and MEK, water vapor content, and temperature. The photocatalytic degradation rate was increased with increasing concentration of acetaldehyde and MEK, but maintained gentle increase beyond a certain concentration. The Langmuir-Hinselwood model was successfully applied to correlate experimental data. Water vapor inhibited the degradation reaction of acetaldehyde and MEK. The optimum reaction temperature was $45^{\circ}C$ for acetaldehyde and MEK.

Photocatalytic Degradation of Rhodamine B Using Carbon-Doped Carbon Nitride under Visible Light

  • Wang, Zhong-Li;Zhang, Zai-Teng;Oh, Won-Chun
    • Korean Journal of Materials Research
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    • v.30 no.6
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    • pp.279-284
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    • 2020
  • In this work, a carbon-doped carbon nitride photocatalyst is successfully synthesized through a simple centrifugal spinning method after heat treatment. The morphology and properties of the prepared photo catalyst are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectrophotometer (UV-vis), and specific surface area. The results show that the band gap of the prepared sample, g-CN-10 is 2.1 eV, is significantly lower than that of pure carbon nitride, 2.7 eV. As the amount of cotton candy increased, the absorption capacity of the prepared catalyst for visible light is significantly enhanced. In addition, the degradation efficiency of Rhodamine B (RhB) by sample g-CN-10 is 98.8 % over 2 h, which is twice that value of pure carbon nitride. The enhancement of photocatalytic ability is attributed to the increase of specific surface area after the carbon doping modifies carbon nitride. A possible photocatalytic degradation mechanism of carbon-doped carbon nitride is also suggested.

Photocatalytic Degradation of a Congo red Using ZnO/rutile-$TiO_2$, ZnO, rutile-$TiO_2$ and CdS (ZnO/rutile-$TiO_2$, ZnO, rutile-$TiO_2$, CdS를 이용한 Congo red의 광 촉매 분해반응)

  • Kim, Chang Suk;Ryu, Hae-Ill
    • Analytical Science and Technology
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    • v.14 no.3
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    • pp.259-265
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    • 2001
  • Photocatalytic degradation of Congo red was performed using various semiconductors as ZnO, CdS, rutile-$TiO_2$ or mixed rutile-$TiO_2$/ZnO. The change of degradation of the dye was investigated by UV-visible spectrophotometric method. The photocatalytic action of CdS was greater than ZnO and rutile-$TiO_2$ in account of low band gap energy of CdS. The rate of photocatalytic degradation reaction increased drastically in according to increasing ratio of ZnO on mixed rutile-$TiO_2$/ZnO. These photocatalytic effect of rutile-$TiO_2$ was suppressed by more stable rutile-$TiO_2$, doping the hydrolysis product with $Zn^{2+}$ prior to calcination onto the rutile-$TiO_2$ surface.

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Effect of Inorganic Salts on Photocatalytic Degradation of Rhodamine B Using Sulfide Photocatalysts under Visible Light Irradiation (가시광선하에서 황화물계 광촉매를 이용한 로다민 B의 광분해 반응에 대한 무기염의 영향)

  • Lee, Gun Dae;Jin, Youngeup;Park, Seong Soo;Hong, Seong Soo
    • Applied Chemistry for Engineering
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    • v.28 no.6
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    • pp.655-662
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    • 2017
  • Sulfide photocatalysts, CdS and CdZnS, were synthesized using a simple precipitation method and their photocatalytic activities were evaluated by the degradation of rhodamine B under visible light irradiation. The effects of four inorganic salt additives, KCl, NaCl, $K_3PO_4$, and $Na_3PO_4$, on the photocatalytic reaction were examined and the role of $K^+$, $Na^+$, $Cl^-$ and $PO_4{^{3-}}$ ions during photocatalytic reaction was discussed. The added inorganic salts were shown to have a remarkable effect on the photocatalytic reaction. It was also found that the anions in inorganic salts have a much more profound effect on the reaction rate, as compared to the cations. Under the present experimental conditions, $PO_4{^{3-}}$ revealed a significant inhibitory effect on the degradation rate whereas $Cl^-$ enhanced the rate slightly. This work pointed out that the consideration of additive effects is needed in the photocatalytic reaction for wastewater treatment.

Photocatalytic Degradation of Trichloroethylene over Titanium Dioxides (이산화티탄에 의한 삼염화에틸렌의 광촉매 분해반응)

  • Lee, Yong-Doo;Ahn, Byung-Hyun;Lim, Kwon-Taek;Jung, Yeon-Tae;Lee, Gun-Dae;Hong, Seong-Soo
    • Applied Chemistry for Engineering
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    • v.10 no.7
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    • pp.1035-1040
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    • 1999
  • Photocatalytic degradation of trichloroethylene has been carried out with UV-illuminated $TiO_2$-coated pyrex reactor in gas phase. Three commercial $TiO_2$ oxides were used as catalysts. The effect of reaction conditions, initial concentration of trichloroethylene, concentration of oxidant and light intensity on the photocatalytic activity were examined. Anatase-type catalyst showed higher activity than rutile-type, but P-25 catalyst showed the highest activity. The degradation rate increased with the decrease of flow rate and initial trichloroethylene concentration. It was preferable to use air as an oxidant. In addition, reactants with the water vapor decreased the activity and the degradation rate increased with the increase of light intensity, but it was very low with solar light. Photocatalytic deactivation was not observed at low concentration of trichloroethylene.

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Preparation of Nb2O5-Graphene Nanocomposites and Their Application in Photocatalytic Degradation of Organic Dyes (Nb2O5-Graphene나노복합체의 제조 및 유기염료 광촉매 분해반응의 응용성에 관한 연구)

  • Park, Hae Soo;Ko, Weon Bae
    • Elastomers and Composites
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    • v.49 no.4
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    • pp.330-335
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    • 2014
  • Niobium pentoxide ($Nb_2O_5$) nanoparticles were synthesized using niobium (V) chloride and pluronic F108NF as the precursor and templating agent, respectively. The $Nb_2O_5$-graphene nanocomposites were placed in an electric furnace at $700^{\circ}C$ and calcined under Ar atmosphere for 2 h. The morphology, crystallinity, and photocatalytic degradation activity of the samples were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and UV-vis spectroscopy. The $Nb_2O_5$-graphene nanocomposites acted as a photocatalyst in the photocatalytic degradation of organic dyes under 254 nm UV light; the organic dyes used were methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and brilliant green (BG). The photocatalytic degradation kinetics for the aforesaid dyes were determined in the presence of the $Nb_2O_5$-graphene nanocomposites.

Degradation Properties of Ibuprofen Using Photocatalytic Process (광촉매 공정에 따른 이부프로펜의 분해 특성)

  • Cai, Jin-Hua;Na, Seung-Min;Ahn, Yun-Gyong;Lee, Se-Ban;Khim, Jee-Hyeong
    • Journal of Environmental Science International
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    • v.21 no.4
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    • pp.411-419
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    • 2012
  • In this study, Ibuprofen (IBP) degradation by the photo catalytic process was investigated under various parameters, such as UV intensity, optimum dosage of $TiO_2$, alkalinity, temperature and pH of bulk solution. The pseudo-first order degradation rate constants were in the order of $10^{-1}$ to $10^{-4}min^{-1}$ depending on each condition. The Photocatalytic IBP degradation rate increased with an increase in the applied UV power. At high UV intensity a high rate of tri-iodide ($I_3{^-}$) ion formation was also observed. Moreover, in order to avoid the use of an excess catalyst, the optimum dosage of catalyst under the various UV intensities (30 and 40 W/L) was examined and ranged from approximately 0.1 $gL^{-1}$. The photo catalytic IBP degradation rate was changed depending on the alkalinity and temperature and pH in the aqueous solution. This study demonstrated the potential of photo catalytic IBP degradation under different conditions.