• 한국산업보건학회지
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• 제18권3호
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• pp.204-215
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• 2008

Many researches for service-life of chemical cartridges of respirators have been performed in many countries. On the result of these researches a few softwares programs were eventually developed to be used. In spite of that, it is difficult to apply these researches and softwares practically in the work spot because of too many factors that influence on service-life of chemical cartridges. This study was the first of two conducted for the purpose of developing program for estimating exchange period or service-life of chemical cartridges available feasibly in the workplaces. Collecting plan of cartridges discarded after use is in principle that three cartridges from three workers at a time, three steps of 1/2 exchange time due to smelling, just routine exchange time and 1.2 to 1.3 expanded time of routine exchange, total nine cartridges are collected in the same job site. 33 cartridges for organic vapor were collected in paint spray process of ship yard and paint factory, and 6 cartridges for acid were collected in plating process. These cartridges were analysed the remaining breakthrough time in 3M Innovation Center. Challenge vapor and breakthrough concentration were complied with Korean regulation for chemical cartridge respirators. Estimated breakthrough time was determined from previously used time plus breakthrough time for the remaining. Exchange period of cartridge would be the shortest time among three estimated breakthrough times. On the result breakthrough time for organic vapor was found to be relatively easily estimated, but that for acid aerosol or vapor was difficult to be confident. Even though this method was difficult to be precisely predicted exchange period of cartridge, it could be an alternative program practically available in the job site.

• 한국환경과학회지
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• 제20권5호
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• pp.667-672
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• 2011

The purpose of this work is to present the experiment results by a dynamic adsorption of water vapor on pelletized zeolites (ADZ300, ADZ400, and ADZ500) in fixed bed. The breakthrough curves of water vapor with several different concentrations and temperature in the range of 25~45 $^{\circ}C$ on zeolite bed were investigated. In the same conditions, the breakthrough time on ADZ400 and ADZ500 were little longer than ADZ300, and the equilibrium adsorption capacity on ADZ500 was highest. The higher the concentration of water vapor was, the faster the breakthrough time was, and the slope of breakthrough curves showed a tendency to increase. The faster the flow rate of water vapor was, the faster the breakthrough time was relatively, but variations between flow rate and breakthrough time did not have a proportional relationship. The breakthrough curve maintained constant gradient in spite of variation of flow rate in the same concentration. The temperature rise in zeolite bed by adsorption heat was occurred in the early stage of adsorption. After water molecule layers were formed on the surface of zeolite, the temperature was slowly cooled by water vapors continuously flowed in as constant temperature. The greater the concentration of water vapor and adsorption temperature were, the temperature difference in zeolite bed was increased.

• 상하수도학회지
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• 제10권3호
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• pp.64-72
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• 1996

The one of the most important factors we shoud consider in designing the processes using porous media such as activated carbon adsorber is the prediction of the breakthrough curve. In this study, the breakthrough curve of BAC process for the treatment of refractory pollutants was evaluated by simplified engineering analysis. Through the experiments, the slope of the breakthrough curve can be determined by retardation factor, R and apparent dispersion coefficient, $D_{app}$ which is determined by hydrodynamic dispersion, mass transfer effects and isotherm. Estimated concentration of effluent was agreed with the experimental values. Also, it is possible to use this method for predicting the breakthrough curve of the pollutants removal and tranport of pollutants in porous media.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.348-351
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• 2005

In this study, solute breakthrough curves through the unsaturated zone were predicted using artificial neural network (ANN) by numerical tests and laboratory experiments. In the numerical tests, applicability of ANN model to prediction of breakthrough curves was evaluated using synthetic data generated by HYDRUS-2D. An appropriate strategy of ANN application and input data form were recommended. The ANN model was validated by laboratory experiments comparing with HYDRUS-2D simulations. The results show that the ANN model can be an effective method for forecasting solute breakthrough curves through the unsaturated zone when hydraulic data are available.

• 한국환경과학회지
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• 제23권9호
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• pp.1593-1600
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• 2014

Adsorption and desorption characteristics of the representative 10 kinds components consisting of gasoline vapor on activated carbon were investigated at the temperature range of $-30^{\circ}C{\sim}25^{\circ}C$. The breakthrough curves of each vapors obtained by the Thomas model were well described the breakthrough experimental results of this study. The breakthrough times of each vapors were correlated with the molecular weight, density, and vapor pressure. The breakthrough times had greater correlation with boiling point than molecular weight and density. The slope of the breakthrough curve was a proportional relationship with the rate constant (k) of Thomas model expression. The higher the slope of the breakthrough curve, the rate constant was larger. The biggest slope vapor had the smallest adsorption capacity ($q_e$). Adsorption and desorption characteristics of mixed vapor similar to the gasoline vapor were studied at room temperature ($25^{\circ}C$). The mixed vapor consisting of 9 components; group A (pentane, hexene, hexane), group B (benzene, toluene), group C (octane, ethylbenzene, xylene, nonane) was examined. Group A was not nearly adsorbed because of substitution by group C, and the desorption capacity of group A was smaller than group C. The adsorbed substances were confirmed to be Group C.

• 공업화학
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• 제16권1호
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• pp.131-138
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• 2005

활성탄과 제올라이트 13X에 대한 벤젠의 정적흡착실험으로부터 Freundlich isotherm과 Toth isotherm을 구하였으며 똑같은 흡착제로 충진된 흡착탑을 이용하여 벤젠의 파과곡선을 측정하였다. 파과시간과 벤젠 분압의 관계를 해석하여 Freundlich isotherm의 파라미터를 결정하였다. 파과실험 결과의 해석으로부터 예측되는 벤젠의 흡착량이 정적 실험 결과로부터 예측되는 것과 비교적 잘 일치하였다. 활성탄에 대한 동적 실험 결과에서 좀 더 대칭형태에 가까운 파과곡선이 얻어져서 제올라이트 13X에 비해 더 적은 오차가 나타났다.

• 한국환경과학회지
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• 제23권1호
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• pp.53-60
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• 2014

Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time ($t_{0.05}$), saturation time ($t_{0.95}$), length of mass transfer zone ($L_{MTZ}$), adsorptive capacity (W), and adsorption rate constant ($K_a$) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer $L_{MTZ}$ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.

• 한국대기환경학회지
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• 제15권2호
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• pp.191-199
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• 1999

This study evaluated the availability as an alternative adsorbent which is cheaper and more efficient than CuO/${\gamma}$-$Al_2O_3$ which have been studing vigorously to remove $SO_2$. Five adsorbents (CuO/${\gamma}$-$Al_2O_3$, Iron ore, Slag, LD slag, $Fe_2O_3$) was employed in a fixed bed reactor. $SO_2$ breakthrough curves were obtained as a function of temperature, initial gas velocity and particle size. Saturation capacities calculated by the numerical integration of breakthrough curves of $SO_2$ increased with increasing reaction temperature. $SO_2$ breakthrough curve equation of $Fe_2O_3$ for this system can be expressed as Kr=3,914,000 exp(-37,329.86/RT). By means of the breakthrough curve, the influence of bed height on breakthrough time was also estimated.

• Carbon letters
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• 제13권2호
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• pp.109-114
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• 2012

A nuclear, biological, chemical (NBC) canister was indigenously developed using active carbon impregnated with ammoniacal salts of copper (II), chromium (VI) and silver (I), and high efficiency particulate aerosol filter media. The NBC canister was evaluated against carbon tetra chloride ($CCl_4$) vapours, which were used as a simulant for persistent chemical warfare agents under dynamic conditions for testing breakthrough times of canisters of gas masks in the National Approval Test of Respirators. The effects of $CCl_4$ concentration, test flow rate, temperature, and relative humidity (RH) on the breakthrough time of the NBC canister against $CCl_4$ vapour were also studied. The impregnated carbon that filled the NBC canister was characterized for surface area and pore volume by $N_2$ adsorption-desorption isotherm at liquid nitrogen temperature. The study clearly indicated that the NBC canister provides adequate protection against $CCl_4$ vapours. The breakthrough time decreased with the increase of the $CCl_4$ concentration and flow rate. The variation in temperature and RH did not significantly affect the breakthrough behaviour of the NBC canister at high vapour concentration of $CCl_4$, whereas the breakthrough time of the NBC canister was reduced by an increase of RH at low $CCl_4$ vapour concentration.

• 멤브레인
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• 제16권4호
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• pp.259-267
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• 2006

다공성 폴리비닐리덴플루오라이드(PVDF, polyvinylidenefluoride) 그리고 폴리테트라플루오르에틸렌(PTFE, Polytetrafluoroethylene)에 대하여 순수한 물, $0.1M{\sim}4.0M$ NaOH 수용액, 그리고 $0.1M{\sim}3.0M\;NaHSO_3$ 수용액을 사용하여 임계투과압력을 측정하였다. 임계투과압력은 동일한 평균 기공 크기의 PVDF보다 PTFE가 크게 나타남을 관찰할 수 있었다. NaOH 수용액의 경우 NaOH의 농도 증가에 따라 임계투과압력은 감소하였으며 1.0 M 농도에서 최소값을 나타낸 후 다시 증가함을 확인하였다. 그러나 NaOH이 아닌 다른 염을 용해한 수용액인 $NaHSO_3$ 수용액의 경우 농도를 3.0 M까지 증가하여도 임계투과압력이 계속 감소함을 알 수 있었다. 이와 같은 현상을 이론적인 Cantor식으로 해석할 수 있었다.