• 환경위생공학
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• 제20권4호통권58호
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• pp.1-8
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• 2005

Pocheon is a basin geographically, and the diffusion of air pollutants is very difficult. Thus, it is essential to consider the characteristics of geographical and weather conditions before industrial complex and various air pollution sources are developed in the area. It is recommended that Environmental Impact Statements (EIS) must be carried out before any action is taken. Constantly occurring fog in the Pocheon area absorbs large amounts of acidic gases, and it transformed into the secondary pollutants such as the salts of sulfate and nitrate. Fog, which occurs very often in Pocheon area, was analyzed for its acid components. Conversion from the gaseous sulfur dioxide into sulfate ion is relatively high, $86\~90\%$ while $68\~76\%$ of NOx is converted into nitrate ion form.

• The Korean Journal of Ecology
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• 제16권1호
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• pp.17-26
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• 1993

We investigated the ph change of water caused by several fuel gases regarded as the main cause of the air pollution, To find out the main cause of increase of the acidity of the rain. We measured it while injrcting each fuel gas directiy to the distilled water. It was observed that bunker-c oil gas and anthracite coal gas were the main cause to make the ph of the solution lowest. We examined the effects of simulated acidic water solutions on several plant species. Simulated acidic rain made by bunker-c oil gas has significant symptom on the saxifraga stolonifera and commelina communis, while no injury was observed on plants exposed to simulated rainfall made by anthracite coal gas.

• 환경위생공학
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• 제10권3호
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• pp.131-138
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• 1995

As the energy consumption increases continuously, the emission amount of air pollutants is growing, and after all it can influence the global environment as welt as the regional atmosphere. So, the clean energy which emits less air pollutants should be developed and widely used to reduce emission of pollutants. Electricity, known for clean energy in the side of consumption, is not actually clean in the process of generation. Electric power is generated using fossil fuels which produce acidic gases like $SO_{2}$, $NO_{x}$, etc. The emission rates of $SO_{2}$, $NO_{x}$, $CO_{2}$ are 2g,0.78g and 1 l0g per electric power generating Ikwh. If one light(60 watt bulb) be turned off at each house for a month electricity will be saved about 1.Skillion kwh a year. This is almost the same as 4,170 tons of $SO_{2}$ and $NO_{x}$. As a result the economization of electricity will be one of the effective strategy to reduce the air pollution and to keep our life clean and comfortable.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2004년도 추계학술대회 논문집
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• pp.119-120
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• 2004

• 한국대기환경학회지
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• 제13권5호
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• pp.333-343
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• 1997

The cyclone/annular denuder system/filter pack sampling system (ADS) was used to collect the acidic air pollutants in Chongju city. The data set was collected on fifty -eight different days with 24 hour sampling period from October 27, 1995 through August 25, 1996. The chemical species measured were HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas phase, and PM2.5( $d_{p}$ ＜2.5 ${\mu}{\textrm}{m}$), S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ and N $H_4$$^{+}$ in the Particulate Phase. Mean concentrations measured for this study were: 0.45 $\mu\textrm{g}$/㎥ for HN $O_3$, 3.39 $\mu\textrm{g}$/㎥ for HN $O_2$, 26.4 $\mu\textrm{g}$/㎥ for S $O_2$, 3.83$\mu\textrm{g}$/㎥ for N $H_3$, 44.2 $\mu\textrm{g}$/㎥ for P $M_{2.5}$, 8.22 $\mu\textrm{g}$/㎥ for S $O_4$$^{2-}$, 3.63 $\mu\textrm{g}$/㎥ for N $O_3$$^{[-10]}$ , and 2.84 $\mu\textrm{g}$/㎥ for N $H_4$$^{- }$. HN $O_3$ and N $H_3$ were higher during the summer. However, HN $O_2$ and S $O_2$ were higher during the fall and winter. P $M_{2.5}$ , S $O_4$/ sup 2-/ and N $H_4$$^{+}$ were not showed seasonal variations, but N $O_3$$^{[-10]}$ was higher in the winter.ter.r.

• 한국지구과학회지
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• 제34권7호
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• pp.681-692
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• 2013

본 연구에서 인공 분기공을 이용해 Giggenbach bottle 법의 적정성을 평가하고, 관련된 전처리 및 분석기술을 확립했다. 인공 분기공은 $CO_2$, CO, $H_2S$, $SO_2$, $H_2$, $CH_4$, HCl, HF, $N_2$의 조합으로 이루어졌고, 각 성분의 유속을 조절해 다양한 조성을 지닌 분기공 가스를 만들었다. 분기공 가스는 NaOH 포집용액이 담긴 병을 사용해 채취했다. CO, $H_2$, $CH_4$의 비용존 가스는 채취병의 빈 공간에 축적되고, $CO_2$, $SO_2$, HCl, HF의 산성가스는 포집용액에 용해된다. $H_2S$ 는 다른 산성가스처럼 포집용액에 용해되나, 카드뮴 아세테이트를 첨가한 경우 $Cd^{2+}$와 반응해 CdS로 침전된다. 비용존 가스는 가스 크로마토그래피를 사용해 분석했다. 한편 포집용액에 생긴 CdS 침전물은 여과장치를 사용해 수용액과 분리시킨 후, $H_2O_2$ 수용액과 반응시켜 CdS 침전물에 결합되어 있는 황화염을 황산염으로 산화시켰다. 또한 침전물이 분리된 포집용액에 $H_2O_2$ 용액을 넣어 아황산염을 황산염으로 산화시켰다. 이런 전처리를 거친 시료는 이온 크로마토그래피를 사용해 분석했다. 포집용액에 용존된 $CO_2$는 전처리 없이 총유기-무기탄소분석기를 사용해 측정했다. 측정된 화산가스의 농도는 인공 분기공에서 설정된 유속과 비례했고, 이는 Giggenbach bottle 법이 화산가스 관측에 유용하게 적용될 수 있음을 나타낸다. 또한 본 연구에서 제시된 전처리 및 분석법은 화산가스 측정의 정확도 및 재현성을 향상시킬 것으로 기대된다.

• 한국환경과학회지
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• 제10권1호
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• pp.59-64
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• 2001

The effect of major operating parameters in spray drying sorber(=SDS) for automatic control for the simultaneous removal of acidic and organic gaseous pollutants from solid waste incinerator was performed. The field experiment was carried out in pilot scale test for the quantification of major operating parameters of hydrophilic and the hydrophobic pollutants. The removal efficiencies of $SO_2$and HCI in the 5wt% slurry condition were being increased with the increase of the stoichiometric ration which is the molecular ratio of lime to the pollutant concentration, and with the decrease of inflow flue gas temperature in the pilot SDS reactor. The removal efficiency along the height of spray drying sorber was closely related to the temperature profile, and more than 90% of total removal efficiency was achieved in an absorption region. For the removal of acidic gas the optimum operating condition considering the economics and a stable operation is the 5wt% of slurry concentration, 1.2 of stoichiometric ratio and 25$0^{\circ}C$ of inflow flue gas temperature. For the organic gases of benzene and toluene the removal efficiencies were 20-60% which is much lower than that of acidic gas. The best removal efficiency was obtained at 1.5 of stoichiometric ratio and 25$0^{\circ}C$ of inflow flue gas temperature. The organic\`s removal efficiency along the height of spray drying sorber was quite different from that of acidic gas, that is, more than 60% of the total removal efficiency for benzene and 90% of the total removal for toluene were achieved in the dried adsorption region, which was formed at the lower or exit part of the reactor.

• 대한화학회지
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• 제13권2호
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• pp.141-147
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• 1969

Organophosphorous compounds can be reduced by zinc metal in acidic solution after alkaline hydrolysis. Although phosphates and phosphonates did not evolve any gas, dithioates did evolve hydrogen sulfide and phosphine, thionates and thiolates did evolve only hydrogen sulfide. The evolved gases were qualitatively detected by means of lead acetate and silver nitrate or mercuric bromide papers and determined by spectrophotometrically. The reduction mechanism and analytical method of dithioates were proposed.

• 한국재료학회지
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• 제24권3호
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• pp.140-144
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• 2014

The contact mechanism of devices is usually researched at electrode contacts. However, the contact between a dielectric and channel at the MOS structure is more important. The graphene was used as a channel material, and the thin film transistor with MOS structure was prepared to observe the contact mechanism. The graphene was obtained on Cu foil by the thermal decomposition method with $H_2$ and $CH_4$ mixed gases at an ambient annealing temperature of $1000^{\circ}C$ during the deposition for 30 min, and was then transferred onto a $SiO_2/Si$ substrate. The graphene was doped in a nitrogen acidic solution. The chemical properties of graphene were investigated to research the effect of nitric atoms doping. The sheet resistance of graphene decreased after nitrogen acidic doping, and the sheet resistance decreased with an increase in the doping times because of the increment of negative charge carriers. The nitric-atom-doped graphene showed the Ohmic contact at the curve of the drain current and drain voltage, in spite of the Schottky contact of grapnene without doping.

• Carbon letters
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• 제4권1호
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• pp.31-35
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• 2003

The specific adsorption behaviors of activated carbons (ACs) treated with 30 wt% $H_3PO_4$ or NaOH were investigated in the removals of NO or $NH_3$. The acid and base values were determined by Boehm's titration method. And, the surface properties of ACs were studied by FT-IR and XPS analyses. Also, $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET and t-plot methods, respectively. From the adsorption tests of NO and $NH_3$, it was revealed in the case of acidic treatment on ACs that the $NH_3$ removal was more effective due to the increase of acidic functional groups in carbon surfaces. Also, the NO removal was increased, in the case of basic treatment, due to the improvement of basic functional groups, in spite of significant decreases of BET's specific surface area and total pore volume. It was found that the adsorption capacity of ACs was not only determined by the textural characteristics but also correlated with the surface functional groups in the acid-base intermolecular interactions.