• 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.

• 한국환경과학회지
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• 제12권12호
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• pp.1255-1260
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• 2003

Plasma-photocatalytic oxidation process was applied in the decomposition of Triethylamine(TEA) and Methyl ethyl ketone(MEK). Plasma reactor was made entirely of pyrex glass and consists of 24mm inner diameter, 1,800mm length and discharge electrode of 0.4mm stainless steel. And initial concentrations of TEA and MEK for plasma-photocatalytic oxidation are 100 ppm. Odor gas samples were taken by gas-tight syringe from a glass sampling bulb which was located at reactor inlet and outlet, and TEA and MEK were determined by GC-FID. For plasma process, the decomposition efficiency of TEA and MEK were evaluated by varying different flowrates and decomposition efficiency of TEA and MEK increased considerably with decreasing treatment flowrates. For photocatalytic oxidation process, also the decomposition efficiency of TEA and MEK increased considerably with decreasing treatment flowrates. The decomposition efficiency of MEK was 57.8％, 34.2％, 18.8％ respectively and the decomposition efficiency of TEA was reached all 100％. This result is higher than that of plasma process only, From this study, the results indicate that plasma-photocatalytic oxidation process is ideal for treatment of TEA and MEK.

• 환경위생공학
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• 제19권2호
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• pp.1-6
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• 2004

In Bok-Jeong water treatment plant, chlorination is the only technique used for disinfection of drinking water. This disinfecting treatment leads to the formation of trihalomethanes (THMs). This study was carried out to investigate the possibility of improving removal efficiency of THM precursor in the conventional water treatment processes by $TiO_2$ photocatalytic oxidation. Removal efficiencies of DOC, $UV_{254}$, THMFP were low in the conventional water treatment processes. With application of $TiO_2$ photocatalyst, DOC, $UV_{254}$, THMFP were reduced more effectively. As the $TiO_2$ photocatalytic reaction time increased, the removal efficiencies of DOC, $UV_{254}$, THMFP were increased. The $TiO_2$ photocatalytic removal efficiencies of DOC, $UV_{254}$, THMFP were increased with increasing $TiO_2$ dosage. However, over 0.6g/l of $TiO_2$ dosage, the efficiency reached a plateau.

• 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.

• Bulletin of the Korean Chemical Society
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• 제14권6호
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• pp.700-704
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• 1993

The photocatalytic alanine and hydrogen production reaction were studied by using CdS as a semiconductor photocatalysts. The rate of alanine and hydrogen production depends strongly on the temperature in heat treatment of CdS powder. In particular, the rate of alanine production, which was observed using Pt/CdS(A)-(CdS from Mitsuwa), was increased about six times than that of using Pt/CdS(B)-(CdS from Furruchi) under the same heat treatment condition at 500$^{\circ}$C. And the photocatalytic activity for alanine production using bare CdS(A) or Pt/CdS(A) was almost same with increasing temperature in heat treatment in the range of 100-600$^{\circ}$C. From X-ray diffraction data and photoluminescence spectrum, we conclude that the crystal structure changes of CdS(A) or strong interaction at interface of Pt and CdS contribute to increasing the rate of alanine and hydrogen production reaction.

• 공업화학
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• 제22권1호
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• pp.61-66
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• 2011

본 연구에서는 이산화티타늄을 솔-젤 방법으로 제조하고 간단한 열처리를 통하여 제조된 이산화티타늄의 물리화학적 특성을 조절하였다. 이들을 메틸렌블루 광분해 반응에 적용한 결과, 473 K에서 열처리한 촉매가 가장 높은 광분해 효율을 보여주었다. 이는 473 K에서 열처리한 촉매가 가장 높은 비표면적($229.8m^2/g$)을 가지고 있고, 이로 인해 메틸렌블루의 흡착이 많이 일어났기 때문인 것으로 보인다. 한편 873 K에서 열처리한 촉매는 낮은 비표면적($23.8m^2/g$) 및 큰 입자 크기(28.38 nm)에도 불구하고 비교적 높은 광촉매 효율을 보여주는데, 이는 고온 열처리로 인한 형성된 rutile 상과 기존의 anatase상의 혼합효과에 기인한 것으로 보인다.

• 멤브레인
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• 제28권3호
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• pp.143-156
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• 2018

본 총설은 다양한 저널 게재 논문으로부터 분리막 및 광촉매의 혼성 정수/하수 처리 공정을 요약하였다. 이 총설에는 (1) 분리막 광촉매 반응기(membrane photoreactor, MPR), (2) 분리막 결합 광촉매 공정에서 막오염 관리, (3) 유기 오염물의 분해를 위한 광촉매 분리막 반응기, (4) 정수처리용 막분리 공정과 광촉매 분해의 결합, (5) 휴믹산 분해를 위한 광촉매 및 세라믹 막여과의 혼성공정, (6) 활성슬러지 여과를 위한 한외여과의 막오염에 이산화티타늄 나노입자의 영향, (7) 정수처리용 광촉매 및 정밀여과의 혼성시스템, (8) 선박 평형수 처리용 한외여과 및 광촉매의 혼성공정 및 (9) 분리막 및 광촉매 코팅 프로필렌 구의 혼성수처리 공정이 포함되어 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1116-1120
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• 2002

Using thermal hydrolysis and hydrothermal treatment, photocatalytic $TiO_2$ powders were synthesized. During the synthesis, the addition of other transition metals such as iron, copper, etc., affected the photocatalytic capability of synthesized powders, and enabled the activation by visible light. To enhance photocatalytic capacity of gas phase decomposition, the rate-determining adsorption rate of pollutant gases were improved via surface modification of $TiO_2$ powders. The surface modifiers were implanted using mechanochemical synthesis of dopants and photocatalytic powders.

• 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.

• Korean Chemical Engineering Research
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• 제57권2호
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• pp.185-197
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• 2019

Deactivation of porous photocatalytic materials was studied using three types of microstructured particles: macroporous titania particles, titania microspheres, and porous silica microspheres containing CNTs and $TiO_2$ nanoparticles. All particles were synthesized by emulsion-assisted self-assembly using micron-sized droplets as micro-reactors. During repeated cycles of the photocatalytic decomposition reaction, the non-dimensionalized initial rate constants (a) were estimated as a function of UV irradiation time (t) from experimental kinetics data, and the results were plotted for a regression according to the exponentially decaying equation, $a=a_0\;{\exp}(-k_dt)$. The retardation constant ($k_d$) was then compared for macroporous titania microparticles with different pore diameters to examine the effect of pore size on photocatalytic deactivation. Nonporous or larger macropores resulted in smaller values of the deactivation constant, indicating that the adsorption of organic materials during the photocatalytic decomposition reaction hinders the generation of active radicals from the titania surface. A similar approach was adopted to evaluate the activation constant of porous silica particles containing CNT and $TiO_2$ nanoparticles to compare the deactivation during recycling of the photocatalyst. As the amount of CNTs increased, the deactivation constant decreased, indicating that the conductive CNTs enhanced the generation of active radicals in the aqueous medium during photocatalytic oxidation.