• 한국대기환경학회지
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• 제24권2호
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• pp.220-228
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• 2008

Toluene adsorption characteristics in the adsorption bed packed with activated carbon fiber (ACF) were studied. Experimental apparatus is composed of VOC generation equipment, adsorption bed, and analytical instrument. Breakthrough characteristics were investigated with length of the adsorption bed which consisted of 3 or 5 sheets of the ACF and flow rate when toluene concentration are 400 ppm and 800 ppm respectively. When mass transfer zone (MTZ) comes out of the adsorption bed, toluene concentration is increased sharply and reached plateau region by saturation. Experimental results are compared with semi-empirical gas adsorption model proposed by Yoon and Nelson. In order to investigate the movement of the MTZ with adsorption time in the adsorption bed packed with ACFs, weight increment of each ACF was measured with the location of ACF at each run. When the weight increment of ACF by toluene adsorption which located at the exit of the bed reaches about 20%, toluene started to be detected.

• 자원리싸이클링
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• 제8권3호
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• pp.26-30
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• 1999

폐주물사 재이용 방안으로 하수처리시 폐주물사를 여재로써 이용하여 인제거에 적용하고져 하였다. 용액의 pH를 2, 6, 11로 조정하여 인제거 실험한 결과 pH2에서 가장 우수한 제거율을 나타내었으며 폐주물산 100g 으로 반응시켰을 경우 2시간의 반응에서 99.9% 이상의 인제거율은 나타내었다. 또한 Langmuir 등온 흡착 모델에 적용한 결과 ${\Gamma}=0.0005{\theta}$/(1+2.4987 $\theta$)의 등온흡착식을 얻었으며 연속식 실험에서 파괴농도를 8mg/l로 하였을 경우 폐주물사의 파과시산은 25hrs으로 나타났다.

• 생명과학회지
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• 제14권1호
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• pp.163-166
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• 2004

정수용 입상활성탄(Granular Activated Carbon, GAC)에서 발생하는 세균 생장 현상을 파악하기 위해 활성탄 칼럼을 제작하고, 수돗물을 고정식 상향류 방식으로 (EBCT = 0.92~1분) 통수시켰다. 봄에는 14일 동안 세균수의 파과(breakthrough) 현상이 없었다. 여름에는 야자계와 석탄계 활성탄 칼럼의 유출 세균수는 비슷하여 파과전에 $10^2$ CFU/ ml수준으로 유입수보다 낮았지만, 10일 이후 유출수가 $10^3$ CFU/ml 로 유입수의 $10^2$ CFU/ml보다 높은 값을 보였다. 칼럼 내부 4지점의 활성탄을 깊이에 따라 분석했을 때 유입수 유입부에 가까울수록 많은 세균수가 관찰되었고 세균군집의 활성은 유사하였다 성장하는 세균은 야자계와 석탄계 활성탄이 서로 달랐지만 Acinetobacter 속이 우점을 이루고 있는 것으로 나타났다.

• 한국환경보건학회지
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• 제19권4호
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• pp.25-32
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• 1993

Granular activated carbon is commonly used in fixed-bed adsorbers to remove organic chemicals. In this experiment organic chemical solutions were prepared by adding the reagent grade organic chemical to distilled water. Isotherm adsorption tests of volatile organic chemicals were conducted using bottle-point technique and column test. Organic chemicals after passing through the column were extracted with hexane and analyzed with gas chromatography (Hewlett-Packard 5890) to check the adsorption capacity and breakthrough curve. The result were as follows: 1. The BET surface area of coconut activated carbon was 658~1,010 m$^2$/g where as coconut shell carbon was 6.6 m$^2$/g. Coconut activated carbon increased the BET surface area and adsorption capacity in bottle-point isotherm. 2. The adsorption capacity of coconut activated carbon for trichloroethylene (TCE) was reduced in the presence of humic substance. 3. A decrease in particle size of activated carbon resulted in higher adsorption capacity and lower intraparticle diffusion coefficient. It is reflected not only as a decrease in Freudlich adsorption capacity value (K) but also as an increase in Freudlich exponenent value (1/n).

• Preventive Nutrition and Food Science
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• 제3권2호
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• pp.123-127
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• 1998

Fixed-bed adsorption was adapted to separate phenolic acids from diluted phenolic solution. Break-through curve was obtained by nonlinear curve fitting method, and breakpoint, saturation time, and mass transfer coeffi-cient were calculated . Break point and saturation time were reached slower with $\rho$-coumaric acid than ferulic acid .The p-coumaric acid, having small molecular weight, is suposedly traveled longer pathway in characoal than ferulic acid. Fixed-bed adsorption iwht gallic acid having more hydroxyl functional group than other phenolic acids showed break point arrival and the largest saturation time. This fact means that there was bigger electrostatic affinity between gallic acid and charcoal than between other phenolic acids and charcoal.

• 공업화학
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• 제26권3호
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• pp.377-380
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• 2015

본 연구에서는 p-diiodobenzene (PDIB)으로부터 p-phenylenediamine (PPD) 합성 후 생성되는 부산물인 $NH_4I$를 PDIB 합성의 원료로 재활용하기 위하여 $I_2$ 회수 공정의 최적화에 관한 연구를 진행하였다. 양이온교환수지를 사용하여 $NH_4I$ 시약 용액으로부터 $I_2$ 회수에 관한 연구를 진행하였고 양이온교환수지의 파과곡선을 통해 파과점 및 관류교환용량을 조사하였다. 회수되는 요오드의 수율 및 순도 향상을 위해 $NH_4I$의 공급용액 및 산화제($H_2O_2$)의 농도 변화, 상온과 저온 건조공정 그리고 산화시간에 따른 순도와 수율을 측정하여 $NH_4I$ 용액으로부터 요오드를 회수하는 공정의 최적조건을 확립하였다. 또한 산화공정 후 발생하는 여액을 재사용하는 과정을 도입하여 실험한 결과 수율 94.96%, 순도 96.65%의 $I_2$를 회수할 수 있었다.

• 한국산학기술학회논문지
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• 제12권5호
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• pp.2439-2444
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• 2011

기존에 주로 사용되었던 활성탄을 대체할 수 있는 활성탄소섬유를 이용하여 휘발성 유기화합물질의 흡 탈착 특성을 연구하였으며, 고정층을 이용하여 흡착 및 파과특성을 조사하였다. 활성탄소섬유중 ACFJ의 경우가 활성탄에 비하여 약1.15배 높은 흡착량을 보였으며, 흡착층의 온도가 증가함에 따라 파과시간 및 흡착량은 감소하였다. 또한 활성탄의 경우 약 99%까지 탈착하는데 20분이 소요되었으며, 활성탄소섬유의 경우 약 99% 탈착되기까지 5분이 걸려 활성탄소섬유가 약 4배 빠르게 탈착됨을 알 수 있었다.

• 한국환경과학회지
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• 제14권1호
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• pp.61-69
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• 2005

Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.856-873
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• 2011

Reversible watermarking is an open problem in information hiding field, with embedding the encoded bit '1' or '0' into some sensitive images, such as the law enforcement, medical records and military images. The technique can retrieve the original image without distortion, after the embedded message has been extracted. Histogram-based scheme is a remarkable breakthrough in reversible watermarking schemes, in terms of high embedding capacity and low distortion. This scheme is lack of capacity control due to the requirement for embedding large-scale data, because the largest hidden capacity is decided by the amount of pixels with the peak point. In this paper, we propose a reversible watermarking scheme to enlarge the number of pixels with the peak point as large as possible. This algorithm is based on an adaptive edge-guided interpolation, furthermore, hides messages by interpolation-error, i.e. the difference between the original and interpolated image value. Simulation results compared with other state-of-the-art reversible watermarking schemes in this paper demonstrate the validity of the proposed algorithm.

• 공업화학
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• 제19권4호
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• pp.366-369
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• 2008

입자상 알루미늄 충전복극조의 성능을 파악할 목적으로 실험은 회분식과 연속식으로 진행하였다. 입자상 알루미늄 충전복극조를 이용하여 T-P 농도 10 mg/L인 인산염 함유 용액을 6 V에서 3 h 회분식으로 전해처리 한 결과 T-P의 제거율은 88% 이었다. 입자상 알루미늄 충전복극조를 이용하여 T-P 농도 10 mg/L인 인산염 함유 용액을 6 V에서 HRT를 3 h으로 하여 연속식으로 전해처리 한 결과 T-P의 농도는 2 mg/L이었다. HRT 3 h으로 고정하여 전해처리 할 경우 120 h 처리 후 파과점을 관찰할 수 있었다.