• 한국대기환경학회지
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• 제16권4호
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• pp.373-380
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• 2000

A new type of photocatalyst plasma air purification filter for decomposition of some VOCs has been developed. The photocatalyst plasma air purification filter employs the pulsed discharge plasma as an energy source of TiO2. photocatalyst instead of UV light. In closed room(2m3) test removal efficiency of some VOCs was 80∼100% in 15∼24 hours. In the initial step of phptocatalyst plasma reaction. Acetone and Nitromethane etc were detected. But they were completely oxidized to CO2 and H2O.

• 전기학회논문지
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• 제56권1호
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• pp.151-155
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• 2007

A compact discharge plasma system with a photocatalyst has been proposed and investigated experimentally for application to air conditioners. It was found that there was intense ultra violet radiation with high energy of 3.2 eV from the corona discharge due to the DC-biased pulse voltage applied on a wire. An electrophotochemical reaction took place apparently on the surfaces of the photocatalyst of $TiO_2$ irradiated ultra violet front the discharge plasma in the proposed plasma system. The proposed discharge plasma system with the photocatalyst of $TiO_2$ showed very high removal efficiency of VOCs by tile additional electrophotochemical reactions on the photocatalyst. The proposed discharge plasma system also showed very high removal efficiency of particles such as smokes, suspended bacteria, and pollen and mite allergens by the electrostatic precipitation part. This type of corona discharge plasma system with a photocatalyst can be used as an effective means of removing both indoor pollutant gases and particles including suspended allergens.

• 전기학회논문지
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• 제58권3호
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• pp.559-565
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• 2009

In this paper, we invented a new and unique technique for the sterilization of Escherichia coli(E. coli) in polluted water. We applied a rich ultra-violet(UV) light from pulsed xenon flashlamp and photocatalyst(TiO2) to sterilize E. coli in polluted water. This method based on the use of UV light and photocatalyst is eco-friendly and does not cause secondary pollution. The proposed elliptical reactor is able to concentrate on quartz sleeve coated TiO2 or general quartz sleeve. The primary objective of our research was to determine the important parameters such as pulse repetition rate and input voltage and to know on the sterilizing efficiency of quartz sleeve coated TiO2 and general quartz sleeve. We obtained to achieve 99.999% sterilization in as little as 6 pulses at 800V in case of quartz sleeve coated Ti02, and 10 pulses at 800V in case of general quartz sleeve for 5 minutes. Although transmitted light of quartz sleeve coated TiO2 is deceased, the sterilizing efficiency is increased by 40% than general quartz sleeve. The reason of high sterilizing efficiency is that generated hydroxyl radical(OH) by photocatalyst and is able to concentrate light at a focus by using elliptical reactor.

• 한국물환경학회지
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• 제31권1호
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• pp.42-48
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• 2015

This study focused on effective decomposition methods for low concentrated organic compounds from the reuse of industrial wastewater, and confirmed the possibility through photocatalyst media. Photocatalyst immobilized media was developed to carry on this experiment which confirmed the removal possibility of low concentrated organic compounds. Considering the stability and efficiency of photocatalyst immobilization, inorganic support, hollow bead, and $TiO_2$ nano powder were used. As a result of the removal experiment, the removal efficiencies of acetonitrile, ethanol, IPA(Isopropyl alcohol), methanol were above 75% after 15 minutes while those of acetone, acetaldehyde, urea were 10%, 45%, 20%, respectively after 60 minutes. If further studies were made to increase the surface area of the photocatalyst immobilized media, the efficiency of the removal of low concentrated organic compounds can be improved and this solution can also be used in an actual treatment process.

• 한국결정성장학회지
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• 제29권6호
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• pp.276-282
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• 2019

본 연구의 목적은 공기청정기의 극세필터(프로필터), 집진필터, 헤파(HAPA-High Efficiency Particulate Air)필터, 탈취필터 등을 사용하는 일반적인 필터의 구조를 분석하고 초미세먼지, 유해가스 및 살균 정화성능을 향상시킬 수 있는 새로운 형태의 공기정화 필터 디자인을 제시하는 것이다. 기존 단계적 여과 필터 형태에 광촉매 필터 시스템을 추가하는 방법으로 연구하였으며, 광촉매 필터는 좌우측의 UV-LED 설치 프레임과 광촉매 코팅 허니컴(honeycomb)프레임 3단 결합구조의 디자인으로 제안했다. 광촉매 필터의 살균소독 효과에 대해서는 향후 연구가 필요하며, 본 연구에서는 공기청정기에 광촉매 필터 적용 및 구조에 대하여 보고하고자 한다.

• 상하수도학회지
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• 제21권6호
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• pp.663-670
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• 2007

This study was performed to provide basic information for evaluating the efficiency and applicable extent of photocatalysis and ozonation for the treatment of dye wastewater. The treatability of dye wastewater by $UV/TiO_2$ and $UV/TiO_2/O_3$ advanced oxidation process (AOP) was investigated under various conditions. The experiments were conducted in a batch reactor of 50 liters equipped with twelve UV Lamps of 16W. In $UV/TiO_2$ AOP, the removal efficiency of TCODMn and Color increased to 58% and 67% respectively with increasing UV intensity. Also, The removal efficiency of TCODMn and Color increased to 97% and 99% respectively with increasing $H_2O_2$. Acid area was more efficient than neutral and alkalic areas in wastewater treatment, and pH 5 was the most effective and the treatment efficiency continually increased as the amount of photocatalyst was increased. When the photocatalyst was increased, TCODMn was removed faster than Color.

• Elastomers and Composites
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• 제51권3호
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• pp.226-232
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• 2016

We studied the photocatalytic functionality such as deodorant, antibacterial, fine dust collection efficiency of polyester-based non-woven fabric filter treated with self-actuated photocatalyst. According to UV/visible result, the UV-visible peak of visible-light responsive photocatalyst was found to be red shift at 420 nm sensitive in the visible light region. The deodorizing performance was shown to be reduced more than 80% even without dark conditions. Fine dust particles collection efficiency was shown to be excellent at the size of not only $2.5{\mu}m{\sim}10.0{\mu}m$ but also less than $2.5{\mu}m$. Also antimicrobial and antifungus was shown to be reduced more than 99.9%.

• 한국재료학회지
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• 제32권1호
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• pp.14-22
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• 2022

To improve light absorption ability in the visible light region and the efficiency of the charge transfer reaction, Pd nanoparticles decorated with reduced TiO₂ nanotube photocatalyst were synthesized. The reduced TiO₂ nanotube photocatalyst was fabricated by anodic oxidation of Ti plate, followed by an electrochemical reduction process using applied cathodic potential. For TiO₂ photocatalyst electrochemically reduced using an applied voltage of -1.3 V for 10 min, 38% of Ti⁴⁺ ions on TiO₂ surface were converted to Ti³⁺ ion. The formation of Ti³⁺ species leads to the decrease in the band gap energy, resulting in an increase in the light absorption ability in the visible range. To obtain better photocatalytic efficiency, Pd nanoparticles were decorated through photoreduction process on the surface of reduced TiO₂ nanotube photocatalyst (r10-TNT). The Pd nanoparticles decorated with reduced TiO₂ nanotube photocatalyst exhibited enhanced photocurrent response, and high efficiency and rate constant for aniline blue degradation; these were ascribed to the synergistic effect of the new electronic state of the TiO₂ band gap energy induced by formation of Ti³⁺ species on TiO₂, and by improvement of the charge transfer reaction.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권10호
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• pp.710-715
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• 1999

The purpose of this work is to develop a high-efficiency air cleaning system for air pollutants such as particulate and gaseous state in indoor environments. In order to enhance a removal efficiency of gaseous state pollutants, we suggested that pulsed discharge plasma be combined with $TiO_2$ photocatalyst (photocatalytic plasma air cleaning unit). We investigated experimentally the basic characteristics of photocatalytic plasma air cleaning unit and measured air pollutants removal efficiency. The wavelength of light radiated from pulsed discharge plasma under the atmospheric condition was 310~380nm. Its energy is enough to excite the $TiO_2$ photocatalyst and it makes a photochemical reaction in the surface of $TiO_2$ photocatalyst. The removal quantity of trimethylamine$((CH_3)_3N)\; was\; 130mg/m^34 which is twice quantity of pulsed discharge plasma without $TiO_2$ phtocatalyst unit. From the result of gas analysis using FT-IR, nitric oxide was not detected and trimethylamine was decomposed to $H_2O\; and \;CO_2$. And trimethylamine removal efficiency was 95%. These experimental results indicate that photocatalytic plasma air cleaning unit is a potential method in removing the pollutants.

• 센서학회지
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• 제31권5호
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• pp.343-347
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• 2022

Recently, the problem of global warming caused by greenhouse gases is getting serious due to the development of industry and the increase in transportation means. Accordingly, the need for a technology to reduce carbon dioxide, which accounts for most of the greenhouse gas, is increasing. Among them, a catalyst for converting carbon dioxide into fuel is being actively studied. Catalysts for reducing carbon dioxide are classified into thermal catalysts and photocatalysts. In particular, the photocatalyst has the advantage that carbon dioxide can be reduced only by irradiating ultraviolet rays at room temperature without high temperature or additional gas. TiO₂ is widely used as a photocatalyst because it is non-toxic and has high stability, but has a disadvantage of low carbon dioxide reduction efficiency. To increase the reduction efficiency, 1-propanol was used in the synthesis process. This prevents agglomeration of the catalyst and increases the specific surface area and pores of TiO₂, thereby increasing the surface area in contact with carbon dioxide. As a result of measuring the CO₂ reduction efficiency, it was confirmed that the efficiency of TiO₂ with 1-propanol and TiO₂ without 1-propanol was 19% and 12.3%, respectively, and the former showed a 1.5 times improved efficiency.