• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 1997년도 종합학술발표회논문집
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• pp.196-202
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• 1997

[6]에서 Zhang과 Zheng은 부울함수의 암호학적인 전역상관계수의 특성을 계산하기 위해서 GAC(Global Avalanche Characteristic)이라는 새로운 개념을 제시하였다. 그들은 GAC의 값들에 대한 측적을 위해서 2개의 단위를 제시했고 2개의 단위의 상한과 하한에 대해서 계산했다. 그러나 그들은 균등함수의 GAC의 하한은 향후의 연구과제로 남겨놓았다. 본 논문에서는 균등함수의 GAC의 하한에 대해서 계산했고, 연접의 방법에 의한 좋은 GAC 의 특성을 가지는 함수의 생성방법을 제시하였다.

• Bulletin of the Korean Chemical Society
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• 제23권6호
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• pp.817-824
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• 2002

Granular activated carbon(GAC) is highly effective in removing organic compounds which are resistant to biological disintegration in wastewater treatment. However, GAC has reached its full adsorptive capacity, GAC needs to be regenerated before it can be used for a further adsorption cycle. Countercurrent oxidative reaction (COR) technique has been developed and evaluated for the regeneration of spent GAC. Various parameters such as flame temperature, the loss of carbon, destruction and removal efficiency (DRE) of organic compounds, surface area, surface structure, adsorptive capacity, etc. were examined to determine the performance of COR. The results of these tests showed that adosorptive capacity of regenerated GAC was completely recovered, the loss of carbon was controllable, flame temperature was high enough to insure complete destruction and removal $(\geq99.9999%)$ of specific organics of interest, polychlorinated biphenyls (PCBs), that are thermally stable, and on formation of toxic byproducts such as polychlorinated dibenzo-p-dioxins (PCDDs) or polychlorinated dibenzofurans (PCDFs) were detected during the regeneration process. The COR technique is environmentally benign, easy to use and less copital intensive than other available regeneration technologies.

• 상하수도학회지
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• 제21권1호
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• pp.13-25
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• 2007

The water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation(KOWACO)'s management, take water from Paldang Reservoir in Han River System for drinking water supply. There are taste and odor (T&O) problems in the finished water because the conventional treatment processes do not effectively remove the T&O compounds. As part of countermeasures for taste and odor control, KOWACO is planning to introduce advanced water treatment process such as ozone and GAC in near future. This study evaluated the removal characteristics of T&O and dissolved organic matter (DOM) to find design and operation parameters of advanced water treatment processes in a pilot-scale treatment plant. The GAC adsorption capacity for DOC in the two GAC system (GAC and $O_3$-GAC) at an EBCT of 14min was mostly exhausted after 9months. The differency of the removal efficiency of DOC between $O_3$-GAC and GAC increased with increasing operation time because the bioactivity in $O_3$-GAC process was enhanced by post-ozone process. Removal by conventional treatment was unable to reach the target TON(threshold odor number) of 3 but GAC systems at an EBCT(empty bed contact time) of 14 min were able to archive the target with few exception. During the high T&O episodes, PAC as a pretreatment together with GAC could be useful option for T&O control. However, substantial TON removal continued for more than two year (> 90,000 bed volumes). At the spiking of less concentration 26 to 61 ng/L in the influent of GAC systems, GAC absorber and $O_3$-GAC processes could meet the treatment target. The better spike control after 12 and 19 months of operation compared to that after 7 months of operation is a strong indication of biological control. The results presented in this study had shown that $O_3$-GAC process was found to be more effective for T&O control than GAC process. And the main removal mechanism in GAC systems were adsorption capacity and biodegradation.

• 한국환경과학회지
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• 제24권9호
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• pp.1163-1170
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• 2015

This study carried out continuous column test for estimating the regeneration efficiency with regeneration times and temperatures. More times regenerated granular activated carbon (GAC) has more ash in the GAC and has less apparent density. Two times regenerated GAC ($2^{nd}$ re-GAC) could removed the Trihalomethanes (THMs) in the water for the first two week after starting continuous column test, on the other hand five times regenerated GAC ($5^{th}$ re-GAC) did not have adsorption capacity. The THMs concentration in the effluent was almost equal or higher than that of influent at the first time of continuous column test. $2^{nd}$ re-GAC showed much more DOC adsorption capacity than $5^{th}$ re-GAC and the GAC which was regenerated with $700^{\circ}C$ had highest DOC removal efficiency among the GACs with 600, 700, 800, $900^{\circ}C$ regeneration temperatures. It is anticipated the cost of GAC regeneration could be saved more 100 million won by reducing the furnace temperature of 3rd~4th and 5th~6th about $150^{\circ}C$ compared to the current regeneration condition.

• KSBB Journal
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• 제19권2호
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• pp.104-109
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• 2004

정수용 입상활성탄 (granular activated carbon, GAC)으로 사용되는 식물계와 석탄계 활성탄의 미생물 재생장 현상을 파악하고 비교하기 위해 활성탄 칼럼을 대상으로, 유입수와 유출수 비교와 함께 활성탄 상의 종속영양세균의 분포와 활성을 분석하였다. 활성탄 칼럼은 총유기탄소와 잔류염소를 잘 제거하였으며 이온은 잘 제거하지 못하는 것을 알 수 있었으며, 칼럼 유출수의 세균수는 10일째 파과 (breakthrough)가 발생한 후 증가하여 최종적으로 석탄계와 식물계 활성탄에서 각각 1.1 ${\times}$ $10^3$, 6.2 ${\times}$ $10^2$ CFU/mL로 나타났다. 칼럼 내부 활성탄 상의 미생물 활성은 GAC-C가 15.35~29.06$\mu\textrm{g}$ INT-formazan/g-GAC/h이었고, 세균수와 세균활성 모두 석탄계가 조금 높았다. 입상활성탄 상의 미생물 재생장 현상이 확인되었고, 석탄계 활성탄이 야자계 활성탄보다 미생물 재생장 유발 효과가 큰 것으로 판명되었으며, 활성탄 상의 세균에 의한 유기물 제거능력이 확인되었다.

• 대한토목학회논문집
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• 제43권4호
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• pp.449-458
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• 2023

용존 유기물을 흡착 제거하는 기술로서, 흡착능이 우수한 입상활성탄을 우선적으로 적용할 수 있지만, 흡착탑의 운전기간에 따라 GAC의 흡착능이 현저히 저하되어 파과되는 한계가 있으며 파과된 활성탄인 spent-GAC는 교체나 재생이 불가피하다. 활성탄 교체는 비용의 경제성 때문에 기피되며 상업적으로 열재생법을 사용하고 있으나, 800℃ 이상의 고온 조건으로 인한 높은 에너지 비용과 활성탄의 질량 손실이 발생하는 단점이 있다. 본 연구에서는 CSOs내의 용존 유기물 처리에 사용된 spent-GAC의 재생효율을 제고하기 위해, Fenton 산화법과 초음파 산화를 융합한 다중산화기술인 Sono-Fenton 방법을 적용하였고, 산화제 주입농도와 초음파 주파수별 spent-GAC의 재생효율을 조사하였다. 적용된 Sono-Fenton 처리에서 Fe²⁺ 10 mmol/L, H₂O₂ 농도 1,000 mmol/L, 120분 초음파 주사시간, 초음파 주파수 40 kHz 재생처리 조건에서 68.5%의 가장 높은 재생효율을 얻을 수 있었고, 750 kHz에서도 유사한 효율을 얻을 수 있었으며, 다른 주파수의 초음파는 재생효율이 불량했고 주파수의 크기와 GAC 재생효율은 선형 관계를 나타내지 않았다. 실 하수를 희석하여 제조한 CSOs로 GAC 흡착탑을 연속운전 한 경우, 재생없이 700시간 내외의 운전이 가능했고 1회의 Sono-Fenton 처리를 적용한 결과, 총 1,000시간의 GAC 흡착 운전 기간 동안 40~70%의 COD_cr 제거 효율이 확보하였다.

• 상하수도학회지
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• 제22권3호
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• pp.323-328
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• 2008

During the full-scale water treatment operation at "G" Water Treatment Plant in Seoul, we investigated changes in pore volume distribution and specific surface area of GAC with time. The pore volume of the used GAC decreased to the level below 0.6 cc/g while that of the brand new GAC was ranged 0.7~0.9 cc/g. The specific surface area of GAC pores changed within the range between $1100{\sim}1200m^2/g$ and $700{\sim}800m^2/g$. Bacteria attached to the surface of GAC shows a gradual increase ($0.4{\time}10^6{\sim}8.5{\time}10^6CFU/g$) under scanninig electron microscope (SEM). TOC removal was enhanced due to growth of the attached bacteria on GAC. It was found that TOC removal was closely related with physical parameters (pore volume, specific surface area) linearly under the investigated conditions. The used GAC need to be exchanged into new one or re-generated to remove organic matters (TOC) effectively from the finished drinking water.

• Asian Journal of Atmospheric Environment
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• 제4권3호
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• pp.177-188
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• 2010

The use of an activated carbon (AC) system alone has the limitation that the pollutants are not eliminated but only transferred to another phase with the consumed AC becoming hazardous waste itself. Therefore, the present study investigated the feasibility of using a combined system of granular AC (GAC) with S-doped visible-light-induced $TiO_2$ (GAC/S-doped $TiO_2$) to clean monocyclic aromatic hydrocarbons (MAHs) with concentrations at $\leq$ 3 mg $m^{-3}$, using a continuous air-flow reactor. This study conducted three different experiments: an adsorption test of pure GAC and GAC/S-doped $TiO_2$; a long-term adsorptional photocatalytic (AP) activity test of GAC/S-doped $TiO_2$; and an AP activity test of GAC/S-doped $TiO_2$ under different conditions. For the AP activity test, three parameters were evaluated: various weights of GAC/S-doped $TiO_2$ (0.9, 4.4, and 8.9 g); various flow rates (FRs) (0.5, 1 and 2 L $min^{-1}$); and various input concentrations (ICs) of the target MAHs (0.1, 1, 2 and 3 mg $m^{-3}$). The adsorption efficiencies were similar for the pure GAC and GAC/S-doped $TiO_2$ reactors, suggesting that S-doped $TiO_2$ particles on GAC surfaces do not significantly interfere with the adsorption capacity of GAC. Benzene exhibited a clear AP activity, whereas no other target MAHs did. In most cases, the AP efficiencies for the target MAHs did not significantly vary with an increase in weight, thereby suggesting that, under the weight range tested in this study, the weights or FRs are not important parameters for AP efficiency. However, ICs did influence the AP efficiencies.

• 상하수도학회지
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• 제35권6호
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• pp.455-463
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• 2021

The adsorption process using GAC is one of the most secured methods to remove of phosphate from solution. This study was conducted by impregnating Cu(II) to GAC(GAC-Cu) to enhance phosphate adsorption for GAC. In the preparation of GAC-Cu, increasing the concentration of Cu(II) increased the phosphate uptake, confirming the effect of Cu(II) on phosphate uptake. A pH experiment was conducted at pH 4-8 to investigate the effect of the solution pH. Decrease of phosphate removal efficiency was found with increase of pH for both adsorbents, but the reduction rate of GAC-Cu slowed, indicating electrostatic interaction and coordinating bonding were simultaneously involved in phosphate removal. The adsorption was analyzed by Langmuir and Freundlich isotherm to determine the maximum phosphate uptake(q_m) and adsorption mechanism. According to correlation of determination(R²), Freundlich isotherm model showed a better fit than Langmuir isotherm model. Based on the negative values of q_m, Langmuir adsorption constant(b), and the value of 1/n, phosphate adsorption was shown to be unfavorable and favorable for GAC and GAC-Cu, respectively. The attempt of the linearization of each isotherm obtained very poor R². Batch kinetic tests verified that ~30% and ~90 phosphate adsorptions were completed within 1h and 24 h, respectively. Pseudo second order(PSO) model showed more suitable than pseudo first order(PFO) because of higher R². Regardless of type of kinetic model, GAC-Cu obtained higher constant of reaction(K) than GAC.

• 분석과학
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• 제19권4호
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• pp.285-289
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• 2006

본 연구에서는 산 표면 처리한 입상 활성탄(GAC)과 활성 탄소섬유(ACF)에 의한 $Pb^{2+}$와 $Ni^{2+}$ 이온의 흡착 특성을 고찰하였다. 산 표면 처리용액으로는 1.0 M 질산 용액을 사용하였다. GAC와 ACF의 표면특성분석은 pH, 등전점(pHpzc), 그리고 원소분석기를 사용하였으며, 비표면적과 기공구조는 77K에서 $N_2$ 등온흡착 방법으로 측정하였다. 본 실험결과 GAC 와 ACF를 산으로 표면 처리한 경우 산소를 포함한 작용기가 증가하였다. 이처럼 산 표면 처리에 의해 증가된 표면 작용기에 따른 GAC 및 ACF의 기공이 막힘에도 불구하고, acidic-ACF > untreated-ACF > acdic-GAC > untreated-GAC 순으로 중금속 흡착능이 증가하였다.