• 임산에너지
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• 제21권2호
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• pp.17-24
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• 2002

소나무 수피로 부터 수증기 활성화 의하여 활성탄을 제조하였으며, 제조된 활성탄은 세공 구조 및 표면적에 대한 검토를 행하였다. 활성화를 위하여 3종류의 서로 다른 형태의 로(정치식 수직, 수평로 및 회전식 수평로)가 본 실험에 사용되었다. 정치식 수직 및 수평로를 이용하여 수피를 탄화시키고 이를 수증기 활성화시키면, 1,000 ㎡／g이상의 높은 비표면적을 얻기는 어려웠다. 분말상태의 시료를 사용하면 비표면적이 약간 향상되었지만, 여전히 정치식 로의 경우 높은 비표면적의 결과를 얻기는 어려웠다. 로타리식 수평로에서 수피를 수증기 활성화시키면, 시판 1급 활성탄과 유사한 1,000 ㎡／g 이상의 비표면적을 나타내는 활성탄을 제조할 수 있었다. 로타리식 수평로에서 제조된 활성탄은 미세공에서 중세공까지 다양한 공극 분포를 나타내었다.

• 상하수도학회지
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• 제22권1호
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• pp.141-148
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• 2008

This study was conducted to evaluate the effect of PAC(Powder Activated Carbon) retention time on stable operation of high concentration powered activated carbon(HCPAC-MBR) in the treatment of secondary domestic wastewater. The pilot scale HCPAC-MBR system was operated at two different SRTs, 25 days and 100 days. The main drawback of HCPAC-MBR system was the rapid increase of trans-membrane pressure. The increase rate of trans-membrane pressure was proportional to SRT value at constant flux. This result seemed to be caused by reduced amount of EPS adsorbed on the PAC in the reactor by decreasing the SRT of the PAC. The particle size of the PAC was also influenced by SRT. The PAC size was decreased as SRT was increased. The change of particle size could be one reason for the change of trans-membrane pressure. The pore volume in the cake-layer formed on the membrane surface became to be increased by reducing SRT, because the cake-layer was highly composed of the PAC. Therefore, increased pore volume might play a role to reduce the trans-membrane pressure. The removal rate of E260 and TOC was also inversely proportional to SRT value.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2468-2473
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• 2018

Nitrogen-doped activated carbon fibers (ACFs) were prepared by chemical vapor deposition using melamine powder and acetonitrile for introducing quaternary nitrogen on the commercial ACFs, subsequently heated at $950^{\circ}C$ and activated by steam. Adsorption experiments of nitrate in aqueous solution were also conducted to evaluate adsorption capacity of the prepared ACFs using ion chromatography. The amount of introduced nitrogen content and nitrogen species on activated carbon fibers was examined by CHN elemental analyzer and X-ray photoelectron spectroscopy, respectively. As a result, adsorption capacity of quaternary nitrogen-doped ACF (ST-ML-AN-ST) was 0.75 mmol/g, indicating ca. two-times higher than that of untreated ACF (0.38 mmol/g). According to the adsorption data, the Langmuir isotherm model was the best fit. The prepared samples were also regenerated using hydrochloric acid. After regeneration, the adsorption capacity of the nitrogen-doped ACF (ST-ML-AN-ST) showed ca. 80% on average, implying that a portion of nitrates was adsorbed on the prepared ACFs irreversibly.

• 한국재료학회지
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• 제25권12호
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• pp.678-682
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• 2015

The electrical property of polymer matrix composites with added carbon powder is studied based on the temperature dependency of the conduction mechanism. The temperature coefficient of the resistance of the polymer matrix composites below the percolation threshold (x) changed from negative to positive at 0.20 < x < 0.21; this trend decreased with increasing of the percolation threshold. The temperature dependence of the electrical property(resistivity) of the polymer matrix composites below the percolation threshold can be explained by using a tunneling conduction model that incorporates the effect of the thermal expansion of the polymer matrix composites into the tunneling gap. The temperature coefficient of the resistance of the polymer matrix composites above the percolation threshold has a positive value; its absolute value increased with increasing volume fraction of carbon powder. By assuming that the electrical conduction through the percolating paths is a thermally activated process and by incorporating the effect of thermal expansion into the volume fraction of the carbon power, the temperature dependency of the resistivity above the percolation threshold can be well explained without violating the universal law of conductivity.

• Carbon letters
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• 제4권4호
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• pp.168-174
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• 2003

Silver nitrate ($AgNO_3$) powder was mixed into a reformed pitch precursor. Then, the silver-containing pitch was melt spun to form round and "C" shape fibers. A wire mesh was inserted prior to the nozzle to improve the spinnability of the silvercontaining precursor pitch. Silver particles in the carbon fibers (CFs) were detected by XRD and TEM. These tests showed that silver particles were uniformly distributed and the total amount of silver remained constant during stabilization and carbonization. Next, the silver-containing CFs were activated by steam diluted in nitrogen gas. Silver particles accelerated the activation rate, but the specific surface areas of the silver-containing ACFs were similar to those of non-silver containing ACFs at the same burn-off levels. The specific surface area of the C-shaped activated carbon fibers was larger than that of the round activated carbon fibers. The likely reason is that the surface area of a C-shaped CF is about two times larger than that of a round CF when equivalent cross-sectional areas are compared. A small amount of silver particles in the periphery of the CFs was removed during the activation, but the remainder of silver was stayed within the ACFs.

• 한국환경과학회지
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• 제17권5호
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• pp.493-500
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• 2008

This paper describes the adsorption/desorpton efficiency of a modified activated carbon by irradiated microwave to treat toluene. By employing microwave energy, the regeneration time was considerably shortened compared with conventional thermal heating regeneration. New adsorbent called ACB (Activated Carbon-Bentonite) was prepared from powder activated carbon with mixing bentonite as a binder. Specific surface area, average pore size and total pore volume of ACB were calculated from the nitrogen adsorption/desorption isotherm. The surface of ACB was characterized with scanning electron microscope(SEM). The results showed that the specific surface area, total pore volume, average pore size of ABC was not influenced by regenerating cycle with microwave irradiation. Toluene was adsorbed onto ACB which desorbed by MW irradiation. Absorption capacity of ACB was 0.117 $g_{toluene}/g_{ACB}$. Desorption efficiency of toluene increased as higher microwave output was applied.

• 한국잠사곤충학회지
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• 제42권2호
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• pp.78-82
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• 2000

In this study, a comparative removal of chlorine from aqueous solutions of mulberry leaf powder(MLP) and activated carbon(AC) was investigated. The chlorine removal capacities of MLP and AC were shown as a function of contact time, pH and initial chlorine concentration. Optimum contact time and removal pH value of MLP were determined as 2 hr and pH 10, respectively. Chlorine removal increased with increasing initial chlorine concentration up to 1.3g/L. Both Langmuir and Freundlich adsorption models were suitable for describing the short-term removal of chlorine by MLP and AC. According to Freundlich adsorption isotherms, the maximum removal capacity of MLP(0.264 mg Cl$_2$/mg) was nearly two times greater than that of AC(0.56 mg Cl$_2$/mg). These results suggested that MLP might potentially be used as an alternative to traditional water treatment materials for removal of residual chlorine in drinking water or process wastewater.

• 한국가구학회지
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• 제22권1호
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• pp.13-17
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• 2011

Recently, interest in indoor air quality is increasing. Especially, radon radioactivity among the indoor air is a well-known risk factor for lung cancer because of ionizing radiation in the form of ${\alpha}$-particles. This study was carried out to investigate effect of black charcoal and activated carbon for reduction of radon radiation that emitted from building materials. Black charcoal and activated carbon were used as a barrier which was against the infiltration of radon. The source of radon was gypsum board. Two types of charcoal barrier were powder- and board-type with 5 mm, 10 mm thickness respectively. The method for this determination is evaluated radon concentration in chamber. The measurements were performed with radon detector, SARAD3120. Results of this study are as following: Black charcoal and activated carbon confirmed the highly efficient barrier. Radon concentration was reduced from 72% to 85% as compared the control chamber. Radon reduction capability, however, was no difference as barrier's types. Results obtained in ventilation condition, radon concentration shows 5.93 pCi/L on average in the closed condition and shows 2.69 pCi/L in the opened condition.

• 한국분말재료학회지
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• 제19권6호
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• pp.424-428
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• 2012

Nano Pd spot-coated active carbon powders were synthesized by a hydrothermal-attachment method (HAA) using PVP capped Pd colloid in a high pressure bomb at $250^{\circ}C$, 450 psi, respectively. The PVP capped Pd colloid was synthesized by the precipitation-redispersion method. PVP capped Pd nano particles showed the narrow size distribution and their particle sizes were less than 8nm in diameter. In the case of nano Pd-spot coated active carbon powders, nano-sized Pd particles were adhered in the active carbon powder surface by HAA method. The component of Pd was homogeneously distributed on the active carbon surface.

• 청정기술
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• 제28권4호
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• pp.285-292
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• 2022

대기 오염의 주요 원인인 휘발성유기화합물(VOCs)의 배출을 저감 하기 위한 방법으로 주로 활성탄 흡착탑이 활용되고 있다. 하지만 활성탄의 짧은 수명과 잦은 교체 주기의 단점이 있어 이를 극복하기 위한 다양한 기술이 개발되고 있으며, 광촉매-활성탄 복합체는 이러한 활성탄의 단점을 극복할 수 있는 방법임을 입증하였다. 광촉매-활성탄 복합체는 활성탄 표면에 금속산화물 광촉매를 코팅하여 광촉매 효과와 활성탄의 흡착능력 효과를 동시에 확보할 수 있는 휘발성유기화합물 저감 물질이다. 미세유체공정을 이용하여 ZnO, 은(Ag) 나노입자를 동시에 합성한 후 실시간으로 ZnO와 은(Ag) 나노입자 용액을 활성탄이 채워진 충진층 반응기에 주입하여 Ag-ZnO 활성탄 복합체를 합성하였다. 합성 반응시간에 따른 광촉매 복합체의 증착양을 분석했으며, 다양한 분석 방법을 통해 광촉매가 활성탄의 기공을 막지 않고 활성탄 표면에 선택적으로 증착 되었음을 확인하였다. 톨루엔 가스백 시험과 흡착 파괴시간 시험을 통해 광촉매-활성탄 복합체가 순수한 활성탄보다 우수한 저감 효과와 지속성을 가지는 것을 확인하였다. 본 연구를 통해 개발된 공정은 광촉매-활성탄 복합체를 효율적으로 생산할 수 있는 방법으로 대량 생산을 위한 스케일 업 공정을 통해 국내의 VOCs 저감 물질 가격 경쟁력을 높일 수 있을 것으로 사료된다.