• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.488-493
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• 2004

The effects were examined from several conditions of $TiO_2$ photocatalysis reaction to phenols degradation by changing it's reacting conditions such as phenol concentration, pH, $TiO_2$ concentration, $H_2O_2$ concentration, flow rate, and intensity of ultraviolet rays. Phenol degradation was more efficient in low concentration of phenol, neutral pH. Phenol degradation appeared to increase as concentration of $TiO_2$ photocatalyst, that of $H_2O_2$ and intensity of ultraviolet rays increased. As $TiO_2$ dosage increased, initial rate constant k linearly increased. When $H_2O_2$ was injected more than optimum, phenol removal rate didn't increase in proportional to the change of $H_2O_2$ concentration as OH radicals was being consumed. When flow rate is less than $4.75m^3/m^2$ day, phenol removal efficiency appeared to decrease as ultraviolet rays transmission rate becomes low by $TiO_2$ suspension coated in photo reaction column. Meanwhile, initial rate constant according to light intensity change in less than $25mW/cm^2$ appeared to be in proportion to light intensity ($mW/cm^2$) Removal efficiency decreased about 12% after 180 minutes of reaction time while showed stable removal efficiency of 100% after 300 minutes when using regenerated $TiO_2$.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2348-2353
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• 2007

In this work, combustion-synthesized $TiO_2$ nanoparticles were used for the photocatalytic degradation of methylene blue with UV light irradiation. Also the results were compared with those of commercial $TiO_2$ nanoparticles (Degussa, P-25). Particle characteristics of the two were analyzed thru the SEM, TEM, and XRD. In spite of the lower specific surface area than that of P-25, the $TiO_2$ nanoparticles formed in this study showed the relatively good ability to degrade the concentration of the organics.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.164.1-164.1
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• 2016

본 연구에서 지지체로 사용된 단결정 형태의 수산화인회석(Hydroxyapatite)은 칼슘과 인산염으로 구성된 무기물이다. 염기 조건 (10 M NaOH)에서 수열합성법 (Hydrothermal method)을 이용하여 단결정 형태의 수산화인회석을 합성하였다. 합성된 단결정 수산화인회석의 표면에 이온 교환 반응을 통하여 은 원자를 도입하였으며, 아르곤 및 수소 기류 (96% Ar, 4% $H_2$) 조건에서 가열하는 온도를 조절하는 것으로 은 나노 입자를 생성시켰다. 합성된 샘플은 XRD 패턴 및 TEM 이미지 분석을 통하여, 수산화인회석의 합성 및 은 나노 입자가 형성된 것을 확인하였다. 합성된 샘플을 유기 반응 촉매로 사용하여 여러 가지 알코올 (1차, 2차 알코올)의 산화 반응에 응용하였으며, UV-Visble light 영역에서의 메틸렌 블루 분해 반응 실험에 광촉매로서 사용하였다.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1277-1284
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• 2003

The photocatalytic oxidation of Rhodamine B (RhB) was studied using immobilized TiO$_2$ and fluidized bed reactor. Immobilized TiO$_2$ onto GF/C 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, air flow rate and anion additives (NO$_3$$\^$-/, SO$_4$$\^$2-/, Cl$\^$-/, CO$_3$$\^$2-/) competing for reaction. The results showed that the optimum dosage of the immobilized TiO$_2$ was 40.0 g/L. Initial removal rate of immobilized TiO$_2$ was expressed Langmuir - Hinshelwood equation.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.495-498
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• 2008

Photocatalytic water splitting into $H_2$ and $O_2$ using semiconductors has received much attention, especially for its potential application to direct production of $H_2$ for clean energy from water utilizing solar light energy. Since the report of Fujishima and Honda on the water splitting by photoelectrochemical cells, numerous different semiconducting materials have been used as photocatalysts for hydrogen generation from water. Among them, platinized titania significantly accelerates hydrogen production from water. For geometrical improvement of $TiO_2$ particle, porous $TiO_2$ structure was proposed and studied such as nanofiber, nanorod and nototubes. This research focuses on finding out the optimum temperature and electrolyte to produce $H_2$ by solar water splitting.

• Journal of Environmental Science International
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• v.13 no.3
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• pp.279-288
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• 2004

This study aimed at improving the $TiO_2$ photocatalytic degradation of HA. A set of tests was first conducted in the dark to study the adsorption of HA at different coexisting material concentration. Adsorption rate increased with adding cation ion but decreased with adding bicarbonate ion. The photodegradation of HA in the presence of UV irradiation was investigated as a function of different experimental condition: initial concentration of HA, $TiO_2$ weight, pH, air flow rate and coexisting material. It was increased either at low pH or by adding cation ion. The increase of cation strength in aqueous solution could provide a favorable condition for adsorption of HA on the $TiO_2$ surface and therefore enhance the photodegradation rate. It was found that bicarbonate ions slowed down the degradation rate by scavening the hydroxyl radicals.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.5
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• pp.521-528
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• 2000

Photocatalyzed degradation of trace level trichloroethylene(TCE) and toluene in air was carried out over near UV illuminated titanium doxide(anatase) pellet in a flow reactor. The authors investigaed the effects of humidity and trace contaminant levels on the oxidation rates of toluene. Inlet concentrations of TCE and toluene were 10∼100ppm. TCE photooxidation was very rapid under what conditions, and almost 100% conversion was achieved for TCE(up to 70 ppm) as a single air contaminant. An important finding was that competitive adsorption between humidity and trace contaminants has a significant effect on the oxidation rate of what.

• Journal of Powder Materials
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• v.10 no.2
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• pp.136-141
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• 2003

In the present study, $TiO_2$ imbedded copper matrix powders have been successfully prepared from the ($CuSO_4+TiO_2+Zn$) composite salt solution. The composite $Cu/TiO_2$ powders were formed by drying the solution at $200{\sim}~400^{\circ}C$ in the hydrogen atmosphere. Photocatalytic characteristics was evaluated by detecting TOC (total organic carbon) amount with TOC analyzer (model 5000A Shimadzu Co). Phase analysis of $Cu/TiO_2$ composite powders was carried out by XRD, DSC and powder size was measured with TEM. The mean particle size of composite powders was about 100 nm and a few zinc and copper oxide phases was included. The reduction ratio of TOC amount was 60% by the composite $Cu/TiO_2$ powders under the UV irradiation for 8 hours.

• Journal of Environmental Science International
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• v.13 no.6
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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.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.577-582
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• 2004

The photocatalytic degradation of atrazine and PCP, a endocrine disruptors, has been investigated over $TiO_2$ photocatalysts under ultraviolet (UV) light irradiation. The effect of operational parameters, i.e., pH, light intensity and persulphate concentration on the degradation rate of aqueous solution of atrazine and PCP has been examined. The results presented in this work demonstrate that, as pH and the light intensity increased, the photocatalytic reaction rates were enhanced. Individual use of $TiO_2$-persulphate was far more effective than using only $TiO_2$ in atrazine and PCP removal. Based on the overall experimental results, the photocatalytic oxidation of atrazine and PCP with the coated $TiO_2$ photocatalyst is found to be very effective under the operational conditions delineated in this study.