• Title, Summary, Keyword: 활성탄소섬유

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Activation of Carbon Fiber in $\textrm{CO}_2$ Gas(l)-Activation process of carbon fiber- ($\textrm{CO}_2$ gas를 이용한 탄소섬유의 활성화(I)-탄소섬유의 활성화 과정)

  • No, Jae-Seung;Seo, Dong-Su
    • Korean Journal of Materials Research
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    • v.8 no.2
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    • pp.114-119
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    • 1998
  • 등방성 피치계 탄소섬유를 Co$_{2}$gas중에서 등온산화시켜 활성탄소섬유를 제조하였다. 산화된 섬유의 비표면적은 BET장치를 이용하여 측정하였다. Burn-off가 증가하여도 반응속도는 크게 감소하지 않았으며, 80$0^{\circ}C$와 90$0^{\circ}C$에서 산화된 섬유의 비표면적은 40%-60%의 burn-off에서 급격히 증가하다가 60%이상에서 감소하였다. 110$0^{\circ}C$에서 산화된 시편은 40%이상 burn-off되어도 비표면적은 크게 증가하지 않고 60%를 지나서도 계속해서 표면적이 증가하는 현상을 나타내었다. 100$0^{\circ}C$에서 60.4%의 burn-off가 일어난 산화섬유의 비표면적은 3,614$m^2$/g로 가장 큰 값이 얻어졌다. 등방성 탄소섬유는 미세한 흑연결정립들이 무질서한 배향을 하고 있으며, 미세기공벽으로 작용할 수 있는 결정립층이 많기 때문에 활성탄소섬유 제조를 위한 원료로 적합하다고 판단된다.

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Preparation of Carbon Electrodes Using Activated Carbon Fibers and Their Performance Characterization for Capacitive Deionization Process (활성탄소섬유를 이용한 탄소전극의 제조 및 축전식 탈염공정에서의 성능평가)

  • Park, Cheol Oh;Oh, Ju Seok;Rhim, Ji Won
    • Membrane Journal
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    • v.28 no.4
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    • pp.271-278
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    • 2018
  • In this study, the carbon electrodes using activated carbon fibers (ACFs) were prepared for the capacitive deionization process. The Polyvinylidene fluoride (PVDF) was used as the binder and the mixed ACFs with proper solvent was cast on the commercial graphite sheets to prepare the carbon electrodes. At this moment, the different particle sizes of ACFs were applied and the mixing ratio of solvent, PVDF and ACFs, 80 : 2 : 18 and 80 : 5 : 15, were used for the electrode preparation. Then their salt removal efficiencies were characterized under the various operating conditions, adsorption potential and time, desorption potential and time, concentration of feed NaCl solution and flow rate as well. Typically, the salt removal efficiency of 53.6% were obtained at the particle size below $32{\mu}m$, mixing ratio 80 : 2 : 18, adsorption 1.2 V and 3 min, desorption -0.1V and 1 min, and 15 mL/min flow rate of NaCl 100 mg/L.

Effect of Oxyfluorination of Activated Carbon Fibers on Adsorption of Benzene Gas Causing Sick House Syndrome (새집증후군 유발 벤젠가스 흡착에 미치는 활성탄소섬유의 함산소불소화 영향)

  • Lim, Hyung Soon;Kim, Min-Ji;Kong, Eun Young;Jeong, Jin-do;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.29 no.3
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    • pp.312-317
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    • 2018
  • In this study, activated carbon fibers (ACFs) were treated by oxy-fluorination to improve the adsorption property of benzene gas, one of the gases causing sick house syndrome. Surface properties and pore characteristics of oxyfluorinated activated carbon fibers were confirmed by X-ray photoelectron Spectroscopy (XPS) and Brunauer-Emmett-Teller (BET), and adsorption properties of benzene gas were evaluated by gas chromatography (GC). As a result of XPS data, it was confirmed that the fluorine functional groups on activated carbon fibers surface increased with increasing the fluorine partial pressure. The specific surface area of all samples decreased after the oxyfluorination treatment, but the micropore volume ratio increased when the fluorine partial pressure was at 0.1 bar. The oxyfluorinated activated carbon fibers adsorbed 100 ppm benzene gas for an 11 h, it was found that the adsorption efficiency of benzene gas was improved about twice as much as that of untreated ones.

Nitric Oxide Sensing Property of Gas Sensor Based on Activated Carbon Fiber Radiated by Electron-beam (전자빔이 조사된 활성탄소섬유 기반 가스센서의 일산화질소 감지 특성)

  • Lee, Sangmin;Jung, Min-Jung;Lee, Kyeong Min;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.28 no.3
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    • pp.299-305
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    • 2017
  • Activated carbon fibers (ACFs) were surface-modified by electron beam (E-beam) irradiation and used as a gas sensor electrode to investigate the effect of E-beam on nitric oxide (NO) gas sensing performance. XPS results showed that the oxygen component of ACFs surface treated by E-beam decreased and $sp^2$ bonded carbon of ACFs surface increased. These results were attributed to the structural transformation of ACFs surface irradiated by E-beam. NO gas sensitivity of the electrode composed of ACFs irradiated by100 kGy increased from about 4% to 8%, and the response time was also meaningfully enhanced from 360 s to 120 s. This is due to the fact that the $sp^2$ carbon bond increased by E-beam irradiation of activated carbon fibers, which significantly affects the resistance change of the electrode in NO gas sensing.

Oxyfluorination of Pitch-based Activated Carbon Fibers for High Power Electric Double Layer Capacitor (고출력 전기이중층 캐패시터를 위한 핏치계 활성탄소섬유의 함산소불소화 처리)

  • Jung, Min-Jung;Ko, Yoonyoung;Kim, Kyung Hoon;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.28 no.6
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    • pp.638-644
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    • 2017
  • Pitch based activated carbon fibers for electric double layer capacitor (EDLC) electrodes were treated by oxyfluorination via varying the ratio of fluorine and oxygen gases to improve high power property. As the partial pressure of fluorine increased, the oxyfluorinated activated carbon fibers showed an increase of linear fluorine functional groups. While the oxygen functional groups increased, no changes was observed with respect to the partial gas pressure. The specific surface area and pore volume decreased due to the etching reaction on the activated carbon fiber surface through oxyfluorination, but the mesopore volume increased about 4.5 times. In the case of activated carbon fibers treated with 50% of the fluorine gas partial pressure, the specific capacitance increased to about 29% and 61% at scan rates of 5 and 50 mV/s, respectively. The improvement of the specific capacitance was believed to be due to the introduction of oxygen and fluorine functional groups on the activated carbon fiber surface and the increase of mesopores through oxyfluorination.

Removal of Trihalomethanes from Tap Water using Activated Carbon Fiber (활성탄소섬유를 사용한 수돗물 내 트리할로메탄의 제거)

  • Yoo, Hwa In;Ryu, Seung Kon
    • Korean Chemical Engineering Research
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    • v.50 no.1
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    • pp.83-87
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    • 2012
  • Activated carbon fiber (ACF) was used to remove four kinds of trihalomethanes(THMs) from tap water which were remained as by-products during the chlorination of water. Adsorption capacity was investigated as a function of THMs concentration and solution temperature, and adsorption mechanism was studied in relating to the surface characteristics of ACF. All the four kinds of THMs were rapidly adsorbed on the surface of ACF by physical adsorption due to the enormous surface micropores and chemical adsorption due to the hydrogen bonds, showing a Langmuir type adsorption isotherm. Langmuir type is especially profitable for the adsorption of low level adsorptives. ACF was very effective for the removal of THMs from tap water because the THMs concentration is below $30{\mu}g/L$ in tap water. The adsorption amount of THMs on ACF increased in order of the number of brom atom; chloroform, bromodichloromethane, dibromochloromethane, and bromoform. The adsorption capacity increased as increasing the number of brom atom due to the decrease of polarity in solution. The adsorption capacity of THMs on ACF can be enhanced by proper surface treatment of ACF.

SO2 Adsorption Characteristics by Cellulose-Based Lyocell Activated Carbon Fiber on Cu Additive Effects (셀룰로오스계 라이오셀 활성탄소섬유의 구리 첨착에 의한 SO2 흡착특성 변화)

  • Kim, Eun Ae;Bai, Byong Chol;Lee, Chul Wee;Lee, Young-Seak;Im, Ji Sun
    • Applied Chemistry for Engineering
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    • v.26 no.4
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    • pp.394-399
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    • 2015
  • In this study, the Cu catalyst decorated with activated carbon fibers were prepared for improving $SO_2$ adsorption properties. Flame retardant and heat treatments of Lyocell fibers were carried out to obtain carbon fibers with high yield. The prepared carbon fibers were activated by KOH solution for the high specific surface area and controlled pore size to improve $SO_2$ adsorption properties. Copper nitrate was also used to introduce the Cu catalyst on the activated carbon fibers (ACFs), which can induce various reactions in the process; i) copper nitrate promotes the decomposition reaction of oxygen group on the carbon fiber and ii) oxygen radical is generated by the decomposition of copper oxide and nitrates to promote the activation reaction of carbon fibers. As a result, the micro and meso pores were formed and Cu catalysts evenly distributed on ACFs. By Cu-impregnation process, both the specific surface area and micropore volume of carbon fibers increased over 10% compared to those of ACFs only. Also, this resulted in an increase in $SO_2$ adsorption capacity over 149% than that of using the raw ACF. The improvement in $SO_2$ adsorption properties may be originated from the synergy effect of two properties; (i) the physical adsorption from micro, meso and specific surface area due to the transition metal catalyst effect appeared during Cu-impregnation process and ii) the chemical adsorption of $SO_2$ gas promoted by the Cu catalyst on ACFs.

Preparation of PAN-based Activated Carbon Fibers by Physical Activation (물리적 활성화에 의한 PAN계 활성탄소섬유의 제조)

  • 임연수;김기원;정승훈;김기덕;정윤중
    • Journal of the Korean Ceramic Society
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    • v.36 no.10
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    • pp.1016-1021
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    • 1999
  • In this study activated carbon fibers were prepared from PAN-based carbon fibers by physical activation with steam or carbon dioxide. The variations in specific surface area amount of iodine adsorption and pore size distribution of the activated carbon fibers after the activation process were discussed. in steam activation BET surface area of about 1019 m2/g was obtained after 77% burn-off while carbn dioxide activation produced ACF with 694m2/g of BET surface area after 52% burn-off. However carbon dioxide activation produced at a similar degree of activation higher micropore volume(0.37 cc/g) and amount of iodine adsorption (1589mg/g) than steam activation. Nitrogen adsorption isotherms for (PAN based activated carbon fibers that prepared by physical activation were of type I in the Brunauer-Deming-Deming-Teller classification

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Liquid Phase Adsorption of Activated Carbon Fibers (활성탄소섬유의 액상흡착)

  • Moon, Dong Cheul;Kim, Chang Soo;Park, Il Yeong;Kim, Mi Ran;Hong, Seung Soo;Lee, Kwang Ho;Lee, Chang Gi
    • Analytical Science and Technology
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    • v.13 no.5
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    • pp.573-583
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    • 2000
  • Activated carbon fibers (ACFs) were prepared from various precursors of plantic, synthetic, and mixed fabrics of viscous rayon and cotton. Their adsorption performances of phenol and methylene blue in aqueous phase were evaluated through their adsorption isotherms, adsorption rates and breakthrough curves. The two adsorbates showed type I adsorption isotherm on ACFs. Adsorption rates to ACFs were 100 fold faster than to GAC. The effective diffusion coefficients of the adsorbates in ACFs were twenty fold greater than in GAC. The ACFs removed completely ten organic pollutants from a prepared water specimens through the 2nd column of a natural filtration method where 50 L of the water samples were treated.

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Gas Adsorption Characteristics of by Interaction between Oxygen Functional Groups Introduced on Activated Carbon Fibers and Acetic Acid Molecules (활성탄소섬유에 도입된 산소작용기와 초산 분자와의 상호작용에 따른 가스 흡착 특성)

  • Song, Eun Ji;Kim, Min-Ji;Han, Jeong-In;Choi, Ye Ji;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.30 no.2
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    • pp.160-166
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    • 2019
  • In this study, oxygen functional groups were introduced on activated carbon fibers (ACFs) by oxygen plasma treatment to improve the adsorption performance on an acetic acid which is a sick house syndrome induced gas. The active species was generated more as the flow rate of the oxygen gas increased during the plasma treatment. For this reason, the specific surface area (SSA) of the ACFs decreased with much more physical and chemical etching. In particular, the SSA of the sample (A-O60) injected with an oxygen gas flow rate of 60 sccm was reduced to about $1.198m^2/g$, which was about 6.95% lower than that of the untreated samples. On the other hand, the oxygen content introduced into the surface of ACFs increased up to 35.87%. Also, the adsorption performance on the acetic acid gas of the oxygen plasma-treated ACFs was improved by up to 43% compared to that of using the untreated ACFs. It is attributed to the formation of the hydrogen bonding due to the dipole moments between acetic acid molecules and oxygen functional groups such as O=C-O introduced by the oxygen plasma treatment.