• 산업기술연구
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• 제20권A호
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• pp.51-56
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• 2000

The Photocatalytic decolorization and degradation of commercial dyes were studied using a batch reactor. Degussa P25 titanium dioxide and $H_2O_2$ were used as the photocatalyst and proved to be effective for dyes degradation when they were irradiated with UV light. The light source was a 20W low pressure mercury lamp. Three different kinds of dyes, such as direct dye(congo red), acid dye (acid black) and disperse dye(disperse blue) were tested. Extending the UV only treatment up to 120min, direct dye was decolorized to 60% and degraded to 30% as COD. On the other side, acid and disperse dyes were eliminated less than 10% as color and COD. But, color and COD were eliminated about 90% for all of the three dyes by $UV/H_2O_2$ system. And then the most effective decolorization was done for direct dye with 96% removal efficiency by $UV/TiO_2$ system at 120min with 500mg/L of $TiO_2$.

• 한국환경보건학회지
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• 제32권4호
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• pp.373-380
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• 2006

The photocatalytic reactor using immobilized $TiO_2$ on silicone sealant was studied bench scale using solar light as the source of radiation. The influences of parameters such as shape, polishing extent and size of reflector, distance between reactor and reflector, an angle of inclination between reactor system and ground, were studies using Rhodamine B (RhB) as a model compound. respectively. The decolorization of round type among the reflector shapes was higher than that of the polygon and W type. The polishing extent of the reflector did not show the decolorization largely. The optimum size of reflector and distance between reactor and reflector were 38 cm and 6 cm, respectively.

• Korean Chemical Engineering Research
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• 제60권1호
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• pp.116-124
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• 2022

교대로 운전되는 광촉매반응기 공정, 및 바이오필터 공정(전통적 바이오필터(L 반응기)와 두 개의 유닛(unit)을 가지는 개선된 바이오필터시스템(R 반응기))로 구성된 통합처리시스템에서, 에탄올과 황화수소를 동시 함유한 폐가스 처리를 수행하는데 발생하는 공정 당 압력강하(△p)와 바이오필터 공정의 미생물 population 분포를 관찰하였다. 교대로 운전되는 광촉매 반응기의 △p는, 바이오필터의 △p와 비교할 때에 무시할 정도로 작게 관찰되었다. L 반응기의 △p는, 통합처리시스템의 운전 중에 계속 증가하여 4.0~5.0 mmH₂O (i.e., 5.0~6.25 mmH₂O/m)로 증가하였다. 한편 R 반응기의 경우에서는 L 반응기의 △p의 약 16~20% 이하인 작은 △p를 나타내었다. 본 연구에서 적용한 공극율이 큰 폐타이어 담체 등의 바이오필터 담체 및 R 반응기 설계의 적용이, 목재 칩(wood chip)과 목재 바크(wood bark)의 50 대 50인 혼합물을 바이오필터 담체로 사용한 전통적 바이오필터의 보고된 압력강하 값의 각각 37~50%와 40~53% 만큼 압력강하 저감에 공헌하였다고 분석되었다. 또한 본 연구의 R 반응기 운전에서 압력강하 값이, 공극율이 큰 화산석(scoria)과 compost를 75 대 25로 혼합한 복합 담체를 충전한 전통적 바이오필터의 보고된 압력강하 값보다 약 80%만큼 저감된 결과는 주로 R 반응기 설계의 적용에 기인하였다고 해석되었다. 한편, 통합처리시스템에서 바이오필터 담체의 microbial population 분포로서 L 반응기 및 R 반응기의 담체 내 미생물 콜로니 수 비교에서는 L 반응기가 제일 밑단에서 다른 윗 단의 콜로니 수보다 거의 두 배로 증가하였으나; R 반응기의 경우는 R_dn 반응기와 R_up 반응기 각각의 상단과 하단에서 고르게 분포하였고 L 반응기보다 콜로니 수가 평균적으로 약 50% 정도 더 컸다. 이러한 현상은 R 반응기의 상단과 하단의 함수율이 50-55%의 고른 분포를 보인 것에 기인하였다. 따라서 개선된 바이오필터시스템이 전통적 바이오필터보다 △p와 미생물 population 분포에서 더욱 우수한 특성을 보였다.

• 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.

• 한국안전학회지
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• 제22권1호
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• pp.24-29
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• 2007

The effectiveness of a UV(ultra violet) disinfection system depends on the characteristics of the waste water, flow conditions, the intensity of UV radiation, the amount of time the microorganisms are exposed to the radiation, and the reactor configuration. The wast water flow conditions are important factors in the design of UV disinfection system from the point of enhancement view of UV disinfection. The turbulent energy intensity in the wake by the vortex shedding are effective for UV radiation. Therewith the effectiveness of vortex generator is considered as a enhancement of UV disinfection. The experimental results presented give important evidences and explain that it is possible to predict UV disinfection performance based on flow experiments. An experimental investigation of two types of the vortex generator is presented. The qualitative and quantitative evaluations of the wake are made by flow visualization using smoke wire method and the measurement of vortex frequencies in the wind tunnel. From the experiment, following results were obtained that the delta wing type vortex generator is more effective than circular type because of the higher vortex frequencies and the smaller drag.

• Environmental Engineering Research
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• 제13권4호
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• pp.197-202
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• 2008

This study evaluated the photocatalytic oxidation of BPA using the RPOD reactor under various conditions. This study found that the RPOD was effective for BPA degradation. It could reduce 1 mg/L of BPA by half within 5 min under the optimum conditions. According to the study results, $TiO_2$ coating was important for the BPA oxidation. As the coating thickness increased, the removal efficiency improved. The light source, the light intensity and the drum rotating speed were important for the oxidation. The UV light was more effective for the BPA degradation than the visible light. The removal efficiency improved with increasing intensity. As the drum speed increased, the removal efficiency improved. The maximum speed was 240 rpm in this study. Addition of air and nitrogen was not beneficial for the BPA degradation in this study probably due to enough oxygen in the water.

• 한국환경과학회지
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• 제23권5호
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• pp.985-993
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• 2014

For the field application of dielectric barrier discharge plasma reactor, a multi-plasma reactor was investigated for the inactivation of microorganisms in sewage. We also considered the possibility of degradation of non-biodegradable matter ($UV_{254}$) and total organic carbon (TOC) in sewage. The multi-plasma reactor in this study was divided into high voltage neon transformers, gas supply unit and three plasma modules (consist of discharge, ground electrode and quartz dielectric tube). The experimental results showed that the inactivation of microorganisms with treated water type ranked in the following order: distilled water > synthetic sewage effluent >> real sewage effluent. The dissolved various components in the real sewage effluent highly influenced the performance of the inactivation of microorganisms. After continuous plasma treatment for 10 min at 180 V, residual microorganisms appeared below 2 log and $UV_{254}$ absorbance (showing a non-biodegradable substance in water) and TOC removal rate were 27.5% and 8.5%, respectively. Therefore, when the sewage effluent is treated with plasma, it can be expected the inactivation of microorganisms and additional improvement of water quality. It was observed that the $NH_4{^+}$-N and $PO{_4}^{3-}$-P concentrations of sewage was kept at the constant plasma discharging for 30 min. On the other hand, $NO_3{^-}$-N concentration was increased with proceeding of the plasma discharge.

• 한국환경과학회지
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• 제13권10호
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• pp.921-928
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• 2004

The photocatalytic decolorization of Rhodamine B (RhB) was studied using immobilized $TiO_2$ and fluidized bed reactor. Immobilized $TiO_2$(length: 1$\~$2 mm, width: 1$\~$3 mm, thickness: 0.5$\~$2 mm) onto silicone sealant was employed as the photocatalyst and a 30 W germicidal lamp was used as the light source and the reactor volume was 4.8 L. The effects of parameters such as the amounts of photocatalyst, initial concentration, initial pH, superficial velocity, $H_2O_2$ and anion additives. ($NO_3^{-},\;SO_4^{2-},\;Cl^{-},\;CO_3^{2-}$) The results showed that the optimum dosage of the immobilized $TiO_2$ were 87.0 g/L. Initial removal rate of RhB of the immobilized $TiO_2$ was 1.5 times higher than that of the powder $TiO_2$ because of the adsorption onto the surface of immobilized $TiO_2$ In the conditions of acidic pH, initial reaction rate was increased slowly and reaction time was shorted. The effect of anion type on the reaction rate was not much.

• 한국환경과학회지
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• 제15권11호
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• pp.1061-1067
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• 2006

Photodegradation of endosulfan alpha, beta, and sulfate known as the most toxic substance among organochlorine pesticides by UV irradiation was studied at experimental conditions such as different pH aqueous solution and reaction time. The initial concentration of endosulfan alpha, beta, and sulfate in aqueous solution was 500 ppb, respectively. The experiment of photodegradation was conducted in a quartz reactor equipped with a low pressure mercury lamp (100 W, 240 nm). The samples were withdrawn from the photo reactor at intervals of 0, 10 min, 30 min, 1 hr, 2 hr, and 4 hr. Endosulfan sulfate was never hydrolyzed and photodegraded in wide range of pH. At pH 5 and reaction time (240 min), endosulfan alpha was photodegraded up to 67%. Both endosulfan alpha and beta were started to photodegrade at pH 6.5 with the lapse of time, resulting in approximately 99.9% and 87.2% of photodegradation efficiency, respectively. Furthermore, at pH 9, endosulfan alpha and beta was partially hydrolyzed and photodegraded to 99.5% at 120 min of reaction time. During the photolysis, any photo-products of endosulfan alpha, beta, and sulfate were not observed.

• 공업화학
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• 제10권1호
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• pp.30-34
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• 1999

클로로타노닐과 엔도슬판을 UV 조사, pH 3.0에서의 UV조사, 그리고 3.5% 염수에서 UV조사를 하여 광분해 거동을 연구하였다. 농약의 광분해과정은 가스크로마토그래프, 총유기탄소, 그리고 이온크로마토그래프를 사용하였다. Low pressure mercury multilamp($8W{\times}6$)를 반응기에 잠수시켜 실험을 하였으며, 초기농도는 10 ppm으로 하였다. 클로로타노닐은 UV 조사, pH 3.0조건에서 UV조사, 그리고 3.5% 염수조건에서 UV조사 조건에서 반응시간 30분에 거의 광분해되었다. 자외선조사에서 엔도슬판-${\alpha}$는 38%, 엔도슬판-${\beta}$는 25% 분해되었다. 엔도슬판-${\alpha}$(83%)는 자외선조사에서 65%, pH 3.0의 자외선조사에서 70%, 35% 염수의 자외선조사에서는 75% 분해되었다. 엔도슬판(16%)는 자외선조사에서 80%, pH 3.0의 자외선조사에서는 98%, 3.5% 염수의 자외선조사에서는 90% 분해되었다.