scholarly journals Activated carbon fibers for toxic gas removal based on electrical investigation: Mechanistic study of p-type/n-type junction structures

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Byong Chol Bai ◽  
Young-Seak Lee ◽  
Ji Sun Im
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Chemical Activation ◽  
Mechanistic Study ◽  
Activated Carbon Fibers ◽  
Gas Removal ◽  
P Type

Abstract In this study, we evaluated the potential use of CuO-ZnO combination structures with activated carbon fibers (ACFs) for the adsorption (by ACFs) and electrochemical detection (by CuO-ZnO) by of SO2 gas. The gas adsorptivity was concluded to improve as a result of the synergetic effects of physical adsorption by the micropores and mesopores, the specific surface area developed by chemical activation and the chemical adsorption reaction between SO2 and the transition metals introduced in the CuO-ZnO combination structures. From comparison of the SO2 sensing properties, the CuO-ZnO combination structures with ACFs exhibited the fastest sensing capability. This result can be attributed to the larger specific surface area of the semiconductor, which extended its depletion layer by forming p-type CuO/n-type ZnO junctions. This phenomenon led to good SO2 detection through a decrease in the resistance; thus, the contributions of the sensing responses of p-type CuO and n-type ZnO represent a predominant characteristic of the sensor. These types of mechanisms were proven through various physicochemical and electrical characterization methods, especially through evaluation of the SO2 sensing capability of the CuO-ZnO combination structures with ACFs. The reversible sensing capability indicates that the p-n junction structure changed the electrical properties of the ACFs, leading to an intriguing sensing mechanism.

Fabrication of Activated Carbon Fibers from Stabilized PAN-Based Fibers by KOH

2004 ◽  
Vol 449-452 ◽  
pp. 217-220 ◽  
Author(s):  
Young Jae Lee ◽  
Jae Hyung Kim ◽  
Jang Soon Kim ◽  
Dong Bok Lee ◽  
Jae Chun Lee ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Potassium Hydroxide ◽  
Chemical Activation ◽  
Activated Carbon Fibers ◽  
High Concentration

Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using potassium hydroxide at different concentration. The experimental data showed variations in specific surface area, microstructure by the activated carbon fibers. Specific surface area of about 2545 m2/g was obtained in the KOH/stabilized PAN-based fiber ratio of 1:1 at 800°. An abrupt reduction of specific surface area was observed in the experiments with the ratio of 3:1 of OH/stabilized PAN-based fiber, being dissimilar with the result of KOH/fiber ratios of 1:1 and 2:1 in the similar experiments. The high concentration of KOH led to the destruction of micropore walls instead of forming mesopores.

Preparation of Activated Carbon Fibers by Chemical Activation Method with Hydroxides

2006 ◽  
Vol 510-511 ◽  
pp. 750-753 ◽  
Author(s):  
Sook Young Moon ◽  
Myung Soo Kim ◽  
Hyun Sik Hahm ◽  
Yun Soo Lim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Chemical Activation ◽  
Lower Surface ◽  
Activation Process ◽  
Temperature Profiles ◽  
Activated Carbon Fibers

Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using hydroxides at different concentrations. The experimental data showed variations in specific surface area, microstructure, pore size distribution, and amounts of iodine adsorbed by the activated carbon fibers. Specific surface area of about 2244m2/g and iodine adsorption of 1202mg/g were obtained in the KOH 1.5M. However, the use of NaOH in the activation process rather than KOH and using the same time/ temperature profiles resulted in a carbon with a much lower surface area. KOH is a more developed pore structure than NaOH, which means that KOH is a better activation agent in producing ACF than NaOH.

Modified polyacrylonitrile-based activated carbon fibers applied in supercapacitor

2016 ◽  
Vol 45 (3) ◽  
pp. 164-171 ◽  
Author(s):  
Linjie Su ◽  
Bohong Li ◽  
Dongyu Zhao ◽  
Chuanli Qin ◽  
Zheng Jin
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Electrode Material ◽  
High Specific Capacitance ◽  
Activated Carbon Fibers ◽  
Content Type

Purpose The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor. Design/methodology/approach In this study, the specific capacitance of ACF was significantly increased by using the phenolic resin microspheres and melamine as modifiers to prepare modified PAN-based activated carbon fibers (MACFs) via electrospinning, pre-oxidation and carbonization. The symmetrical supercapacitor (using MACF as electrode) and hybrid supercapacitor (using MACF and activated carbon as electrodes) were tested in term of electrochemical properties by cyclic voltammetry, AC impedance and cycle stability test. Findings It was found that the specific capacitance value of the modified fibers were increased to 167 Fg-1 by adding modifiers (i.e. 20 wt.% microspheres and 15 wt.% melamine) compared to that of unmodified fibers (86.17 Fg-1). Specific capacitance of modified electrode material had little degradation over 10,000 cycles. This result can be attributed to that the modifiers embedded into the fibers changed the original morphology and enhanced the specific surface area of the fibers. Originality/value The modified ACFs in our study had high specific surface area and significantly high specific capacitance, which can be applied as efficient and environmental absorbent, and advanced electrode material of supercapacitor.

scholarly journals Coconut-based activated carbon fibers for efficient adsorption of various organic dyes

RSC Advances ◽  
2018 ◽  
Vol 8 (74) ◽  
pp. 42280-42291 ◽  
Author(s):  
Ling Zhang ◽  
Ling-yu Tu ◽  
Yan Liang ◽  
Qi Chen ◽  
Ze-sheng Li ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Organic Dyes ◽  
Low Cost ◽  
Micropore Volume ◽  
Activated Carbon Fibers ◽  
Large Specific Surface Area

Activated carbon fibers with high micropore volume and large specific surface area were prepared from abundant and low-cost coconut fibers, which show excellent adsorption performances towards various dyes.

scholarly journals Pitch-Derived Activated Carbon Fibers for Emission Control of Low-Concentration Hydrocarbon

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1313 ◽  
Author(s):  
Hye-Min Lee ◽  
Byeong-Hoon Lee ◽  
Soo-Jin Park ◽  
Kay-Hyeok An ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Volume Fraction ◽  
Structural Characteristics ◽  
Total Pore Volume ◽  
Activated Carbon Fibers

The unburned hydrocarbon (HC) emissions of automobiles are subject to strong regulations because they are known to be converted into fine dust, ozone, and photochemical smog. Pitch-based activated carbon fibers (ACF) prepared by steam activation can be a good solution for HC removal. The structural characteristics of ACF were observed using X-ray diffraction. The pore characteristics were investigated using N2/77K adsorption isotherms. The butane working capacity (BWC) was determined according to ASTM D5228. From the results, the specific surface area and total pore volume of the ACF were determined to be 840–2630 m2/g and 0.33–1.34 cm3/g, respectively. The butane activity and butane retentivity of the ACF increased with increasing activation time and were observed to range between 15.78–57.33% and 4.19–11.47%, respectively. This indicates that n-butane adsorption capacity could be a function not only of the specific surface area or total pore volume but also of the sub-mesopore volume fraction in the range of 2.0–2.5 nm of adsorbents. The ACF exhibit enhanced BWC, and especially adsorption velocity, compared to commercial products (granules and pellets), with lower concentrations of n-butane due to a uniformly well-developed pore structure open directly to the outer surface.

scholarly journals Characterization of Activated Carbon Fibers

1990 ◽  
Vol 209 ◽  
Author(s):  
A. W. P. Fung ◽  
A. M. Rao ◽  
K. Kuriyama ◽  
M. S. Dresselhaus ◽  
G. Dresseliiaus ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Disordered Systems ◽  
Activated Carbon Fibers ◽  
Characterization Of Activated Carbon

AbstractLow-temperature electrical conductivity and Raman scattering are studied as characterization tools for activated carbon fibers, which have a high density of defects and a huge specific surface area. The transport mechanism at low temperature is governed by variablerange hopping, as in other strongly disordered systems. From the Raman spectra obtained, we deduce that the long phenolic fibers are more disordered than the acrylic fibers and that increased specific surface area corresponds to increased disorder. The average in-plane microcrystallite size is about 20–30 Å.

Characterization of Flame-Generated TiO2 Deposited Activated Carbon Fibers (ACF)

2007 ◽  
Vol 544-545 ◽  
pp. 31-34
Author(s):  
Jae Hong Park ◽  
Jun Ho Ji ◽  
Jeong Hoon Byeon ◽  
Gyo Woo Lee ◽  
Jung Ho Hwang
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Hydrogen Diffusion ◽  
Flame Temperature ◽  
Sampling Location ◽  
Activated Carbon Fibers ◽  
Tio2 Particles

Even though activated carbon fibers (ACF) have been attractive due to high specific surface area and uniform micropore structure, there are only a few reports about the photocatalyst immobilization on ACF or their photodegradation behavior for removal of organic pollutants. In this study, ACF were selected as adsorptive support for photocatalyst immobilization. As photocatalysts, TiO2 nanoparticles were synthesized by using a N2-diluted and oxygen-enriched co-flow hydrogen diffusion flame. The visible flame length of 150mm was obtained by direct photographs. Flame temperature was measured by rapid insertion measurement technique with a R-type (Pt/Pt-13%Rd) thermocouple which was in wire shape (127μm diameter). TiO2 particles were sampled by using a high temperature particle sampler and then were coated on ACF filters. The sampling was carried out at 70mm and 110mm above the burner. The structure of TiO2 particles was analyzed by XRD. TiO2 coated ACF filters were characterized by FESEM-EDX and BET analyses. TiO2 particles on ACF filters were found to be agglomerated particles and the size of primary particles was approximately 50nm. The structure of TiO2 particle was anatase-phase crystalline structure. The specific surface area of TiO2 coated ACF filter was enhanced to be 1700~1860m2/g, depending on the sampling location, and the pores were micropores, regardless of the sampling location.

Production and characterization of lignocellulosic biomass-derived activated carbon

2010 ◽  
Vol 62 (11) ◽  
pp. 2637-2646 ◽  
Author(s):  
A. B. Namazi ◽  
C. Q. Jia ◽  
D. G. Allen
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Lignocellulosic Biomass ◽  
Specific Surface Area ◽  
Chemical Activation ◽  
Pulp Mill ◽  
Activation Process ◽  
Activation Temperature ◽  
Biomass Ratio

The goal of this work is to establish the technical feasibility of producing activated carbon from pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials, two sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigated experimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activation temperature (400–600°C) and activation time (1 to 2 h) on the development of porosity. The activation products were characterized for their physical and chemical properties using a surface area analyzer, scanning electron microscopy and Fourier transform infrared spectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosic biomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organic molecules. The results show that the activated carbon are highly porous with specific surface area greater than 500 m2/g. The yield of activated carbon was greater than the percent of fixed carbon in the dry sludge, suggesting that the activation process was able to capture a substantial amount of carbon from the organic matter in the sludge. While 400°C was too low, 600°C was high enough to sustain a substantial rate of activation for linerboard sludge. The KOH/biomass ratio, activation temperature and time all play important roles in pore development and yield control, allowing optimization of the activation process. MB adsorption followed a Langmuir isotherm for all four activated carbon, although the adsorption capacity of NK-primary sludge-derived activated carbon was considerably lower than the rest, consistent with its lower specific surface area.

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