• 한국대기환경학회지
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• 제24권3호
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• pp.329-335
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• 2008

Volatile organic compounds emitted to the atmosphere can cause adverse effects on human health and participate in photochemical smog formation reactions. The destruction of a series of VOCs has been carried out by non-thermal plasma in other researches. And the characteristic of non-thermal plasma was operated at atmospheric pressure and low temperature. A new type non-thermal plasma reactor was investigated combined Glidarc plasma with water jet in this research. Also, it was found that the water-jet had an significant effect on the toluene removal efficiency. But too much water content does not favor toluene decomposition by decreasing of reaction temperature. The input toluene concentration, gas flow rate, water flow rate and specific energy input were used as experiment variables. The toluene removal efficiency, energy efficiency and specific energy input were 75.3%, 146.6 g/kWh and $1.12kWh/m^3$ at a water flow rate of 100 mL/min.

• Korean Chemical Engineering Research
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• 제56권3호
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• pp.356-360
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• 2018

인구증가와 개발 도상 국가의 산업 활동 증가로 인해 대기 중 미세먼지농도가 상승함에 따라 생태계에 미치는 영향이 심각해지고 있다. 그로인해 미세먼지발생을 줄이기 위한 정책을 수립하여 시행하거나 미세먼지를 여과해주는 공기청정기나 마스크의 연구가 활발히 이루어지고 있다. 본 연구에서는 전기방사실험을 통해 셀룰로스 아세테이트 파이버 필터를 제조하고 고분자용액에 활성탄을 첨가하여 미세입자 제거에 미치는 활성탄의 영향을 평가하였다. 미세입자 생성을 위해 염화나트륨 수용액을 사용하였으며, 공기 중 수분의 영향을 배제하기 위해 건조기를 설치하여 수분을 제거한 후 필터 성능을 분석하였다. 활성탄이 첨가될수록 미세입자 제거 효율은 증가하였으며, 아세톤 흡착량 또한 증가하였다.

• 한국환경과학회지
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• 제7권3호
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• pp.301-310
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• 1998

Recently, bathes have been suspected to an Important source of indoor exposure to volatile organic compounds(VOCs). Two experiments were conducted to evaluate chloroform exposure and corresponding body burden by exposure routes while bathing. Another experiment was conducted to ekamine the chloro- form dose during dermal exposure and the chloroform decay In breath after dermal exposure. The chioroform dose was determined based on exhaled breath analysis. The ekamine breath concentration measured after normal baths (2.8 Vg/$m^3$) was approxidmately 13 tomes higher that measured prior to normal bathes (0.2 ug/$m^3$). Based on the means of the normalized post exposure chloroform breath concentration. the dermal exposure was estimated to contribute to 74% of total chloroform body burden while bathing. The Internal dose from bathing (Inhalation plus dermal) was comparable to the dose ostimated Srom dally water Ingestion. The rusk associated 10 a weekly, 30-min bath was estimated to be 1 x 10.5, while the rusk firom dally Ingestion of tap water was to be $0.5{\times}0^{-5} for 0.151 and 6.5{\times}10^{-5}$ for 2. 0 1. Chloroform breath concentration Increased gradually during the 60 minute dermal exposure. The breath decay after the dermal exposure showed two-phase mechanism, with early raped decay and the second slow decay. The mathematical model was developed to describe the relationship between water and air chloroform concentrations, with $R^2$ : 0.4 and p<0.02.

• 한국환경과학회지
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• 제11권12호
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• pp.1267-1274
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• 2002

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using ozonation process. For raw water, Nakdong River was used. By conducting batch test of ozonation, the following results were obtained. When ozone dosage of $5 mg/{\ell}$ was used, ozone transfer and utilization efficiencies of the ozonation were 94 to 92%, respectively. Removal efficiencies of single VOC compound or mixed VOC compounds in the raw water were 80% to 90% by the ozonation with $2 mg/{\ell}$ dosage and 10 minutes contact time. Removal efficiencies of ABS by the ozonation with $1 mg/{\ell}$, $3 mg/{\ell}$ dosage and 20 minutes contact time were 83% to 96%, respectively. Almost 67% of chlorophyll-a at the concentration of $38.4\mu\textrm{g}/{\ell}$ was removed by ozonation at ozone dosage of $1 mg/{\ell}$ for 20 min. Considering the efficiency of ozone utilization and water treatment, the most effective ozonation could be obtained with high ozone dosage and short contact time.

• 한국환경과학회지
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• 제11권12호
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• pp.1253-1259
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• 2002

This study analyzes the surface ozone, NO and $NO_2$ concentration data from 1997 to 1999 in Daegu. It investigates effect on precursor during high-ozone episode days. The high-ozone episode is defined when a daily maximum ozone concentration is higher than 100 ppb(ambient air quality standard of Korea) in at least one station among six air quality monitoring stations. The frequency of episodes is 13 days(33 hours). The frequency is the highest in May and September, and the area with the highest frequency is Nowondong and Manchondong. The average value of daily maximum ozone concentration with high ozone episode is 81.6 ppb, and that of 8-hour average ozone concentration is 58.6 ppb. It means that ozone pollution is continuous and wide-ranging in Daegu. The daily variation of NO, $NO_2$ and $O_3$ in high-ozone episodes are inversely proportional one another. Nowondong an industrial area, is affected by pollutants that are emitted from the primary sources, while Manchondong a residential area, is affected by the advection of $O_3$ or by the primary pollutants like VOCs.

• 환경영향평가
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• 제14권3호
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• pp.109-115
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• 2005

This study was conducted to evaluate the efficiency of indoor air cleaners and to inform how to select them correctly to the users. The efficiencies of removing suspended bacteria per hour were $64.3{\pm}13.1%$ for filter, wet, and complex type, respectively, which showed the complex type was the most efficient. The removal efficiencies of formaldehyde (HCHO) after two hours operation of air cleaners showed 88.3% and 81.1% for filter and wet type, respectively. The efficiency of complex type, with removal rate of 55.5~58.4%, was decreased after 30 minutes operation. Therefore, it is recommended to perform over 60 minutes when doing air cleaner certification test for HCHO removal efficiency. Generally, air cleaners having low wind volume showed higher efficiency. All tested air cleaners had no potential for removing of volatile organic compounds (VOCs), which is toxic substances, and it is desirable to develop a device which can control these substances. The results also confirmed that there was no ozone production from all tested air cleaners. And it is recommended to ventilate for 20 minutes every four hours to maintain 50% ventilation status.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.91-91
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• 2012

We aim in synthesizing various functional thin films thinner than ~ 10 nm for environmental applications and photovoltaic devices. Atomic layer deposition is used for synthesizing inorganic thin films with a precise control of the film thickness. Several examples about application of our thin films for removing volatile organic compounds (VOC) will be highlighted, which are summarized in the below. 1) $TiO_2$ thin films prepared by ALD at low temperature ($<100^{\circ}C$) show high adsorption capacity for toluene. In combination with nanostructured templates, $TiO_2$ thin films can be used as building-block of high-performing VOC filter. 2) $TiO_2$ thin films on carbon fibers and nanodiamonds annealed at high temperatures are active for photocatalytic oxidation of VOCs, i.e. photocatalytic filter can be created by atomic layer deposition. 3) NiO can catalyze oxidation of toluene to $CO_2$ and $H_2O$ at $<300^{\circ}C$. $TiO_2$ thin films on NiO can reduce poisoning of NiO surfaces by reaction intermediates below $200^{\circ}C$. We also fabricated inverted organic solar cell based on ZnO electron collecting layers on ITO. $TiO_2$ thin films with a mean diameter less than 3 nm on ZnO can enhance photovoltaic performance by reducing electron-hole recombination on ZnO surfaces.

• 한국환경과학회지
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• 제21권10호
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• pp.1195-1202
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• 2012

The purpose of this work is to study the adsorption and desorption characteristics of acetone vapor and toluene vapor from adsorption tower in the VOCs recovery device. The six kinds of activated carbon with different pore structures were used and the adsorption and desorption characteristics were compared according to pore structure, desorption temperature, and adsorption method, respectively. Adsorption capacity of acetone vapor and toluene vapor by batch method was higher than that by dynamic method. Especially, activated carbon with medium-sized or large pores had more difference in adsorption capacity according to adsorption methods as a result of gradually condensation of vapors on relatively mesopore and large pores. Activated carbons with relatively large pores and relatively small saturated adsorption capacity had excellent desorption ability.

• 한국군사과학기술학회지
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• 제15권4호
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• pp.475-491
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• 2012

Green Chemistry emerged at the end of 20th century, which aims the development of the technologies for the sustainable society at the molecular level. Most products we consume in everyday life are produced through chemical processes, and we often oversee the fact that huge amount of solvents are used and disposed. At the present time most solvents used in laboratories as well as industries are volatile organic compounds(VOC), which gives health and environmental problems. Therefore scientists are seeking new materials which have equivalent properties of VOCs as solvent, and at the same time gives no health and environmental problems. In this brief review, the author describes the present status of research and development activities of green solvent materials throughout research societies worldwide. At present the most attractive green solvent candidates are water, glycerol, supercritical carbon dioxide and ionic liquids. In order to give the pictures of these materials, the author tried to introduce the overall aspects of green solvents in various chemical reaction as well as catalytic roles.

• 한국재료학회지
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• 제29권3호
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• pp.143-149
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• 2019

To develop flexible adsorbents for compact volatile organic compound (VOC) air purifiers, flexible as-spun zeolite fibers are prepared by an electrospinning method, and then zeolite particles are exposed as active sites for VOC (toluene) adsorption on the surface of the fibers by a thermal surface partial etching process. The breakthrough curves for the adsorption and temperature programmed desorption (TPD) curves of toluene over the flexible zeolite fibers is investigated as a function of the thermal etching temperature by gas chromatography (GC), and the adsorption/desorption characteristics improves with an increase in the thermal surface etching temperature. The effect of acidity on the flexible zeolite fibers for the removal of toluene is investigated as a function of the $SiO_2/Al_2O_3$ ratios of zeolites. The acidity of the flexible zeolite fibers with different $SiO_2/Al_2O_3$ ratios is measured by ammonia-temperature-programmed desorption ($NH_3-TPD$), and the adsorption/desorption characteristics are investigated by GC. The results of the toluene adsorption/desorption experiments confirm that a higher $SiO_2/Al_2O_3$ ratio of the flexible zeolite fibers creates a better toluene adsorption/desorption performance.