• Journal of Industrial Technology
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• v.20 no.A
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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 $TiO_2$.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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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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• v.60 no.1
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• pp.116-124
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• 2022

In this study, waste air containing ethanol and hydrogen sulfide, was treated by an integrated hybrid system composed of two alternatively-operating UV/photocatalytic reactor-process and biofilter processes of a biofilter system having two units with an improved design (R reactor) and a conventional biofilter (L reactor). Both a pressure drop (△p) per unit process of the integrated hybrid system and a microbe-population-distribution of each biofilter process were observed. The △p of the UV/photocatalytic reactor process turned out very negligible. The △p of the L reactor was observed to increase continuously to 4.0~5.0 mmH₂O (i.e., 5.0~6.25 mmH₂O/m). In case of R reactor, its △p showed the one below ca. 16~20% of the △p of the L reactor. Adopting such microbes-carrying biofilter media with high porosity as waste-tire crumb media, and the improved biofilter design, contributed to △p of this study, reduced by ca. 37~50% and 40~53%, respectively, from the reported △p of conventional biofilter packed with biofilter media of the mixture (50:50) of wood chip and wood bark. In addition, the △p of R reactor in this study, reduced by ca. 80% from the reported △p of conventional biofilter packed with biofilter media of the mixture (75:25) of scoria with high porosity and compost, was mainly attributed to adopting the improved biofilter design. On the other hand, in case of L reactor, the CFU counts in its lowest column was analyzed double as much as those in any other columns. However, in case of R reactor, its CFU counts were bigger by 50% than the one of L reactor and its microbes were evenly distributed at its higher and lower columns of R_dn reactor and R_up reactor. This phenomena was attributed to an even moisture distribution of 50~55% of R reactor at its higher and lower columns. Therefore, R reactor showed superb characteristics in terms of both △p and microbe-population-distribution, compared to L reactor.

• Journal of Wetlands Research
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• v.9 no.1
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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.

• Journal of the Korean Society of Safety
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• v.22 no.1 s.79
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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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• v.13 no.4
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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.

• Journal of Environmental Science International
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• v.23 no.5
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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.

• Journal of Environmental Science International
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• v.13 no.10
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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.

• Journal of Environmental Science International
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• v.15 no.11
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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.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.30-34
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• 1999

Photolysis behavoirs of pesticides(Chlorothalonil and Endosulfan) over UV irradiation UV irradiation with pH 3.0 and irradiation with 3.5% salt were studied. The analyses of pesticides were carried out using gas chromatograph with an electron-capture detector, total organic carbon, and Ion chromatograph, respectively. The reactions were conducted in a alumium annular reactor equipped with a low pressure mercury multilamp ($8W{\times}6$) and initial concentration was 10 ppm. Chlorothalonil was almost photodegraded by UV irradiation, UV irradiation with pH 3.0 and 3.5% salt within 30 min of reaction time. Endosulfan-${\alpha}$,${\beta}$(100%) were photodegraded to 38% of Endosulfan-${\alpha}$ and 25% of Endisulfan-${\beta}$ by UV irradiation. Endosulfan-${\alpha}$(83%) was photodegraded to 66% by UV irradiation, 70% by UV irradiation and pH 3.0 and 75% by UV irradiation and 3.5% salt. Endosulfan-${\beta}$(16%) was photodegraded to 80% by UV irradiation, 98% by UV irradiation and pH 3.0 and 90% by UV irradiation and 3.5% salt.