scholarly journals Carbon Dioxide Adsorption on Porous and Functionalized Activated Carbon Fibers

2019 ◽  
Vol 9 (10) ◽  
pp. 1977 ◽  
Author(s):  
Yu-Chun Chiang ◽  
Cheng-Yu Yeh ◽  
Chih-Hsien Weng
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Co2 Adsorption ◽  
Physical Adsorption ◽  
Koh Activation ◽  
Co2 Uptake ◽  
Activated Carbon Fibers

Polyacrylonitrile-based activated carbon fibers (ACFs), modified using potassium hydroxide (KOH) or tetraethylenepentamine (TEPA), were investigated for carbon dioxide (CO2) adsorption, which is one of the promising alleviation approaches for global warming. The CO2 adsorption isotherms were measured, and the values of isosteric heat of adsorption were calculated. The results showed that the KOH-modified ACFs exhibited a great deal of pore volume, and a specific surface area of 1565 m2/g was obtained. KOH activation made nitrogen atoms easily able to escape from the surface of ACFs. On the other hand, the surface area and pore volume of ACFs modified with TEPA were significantly reduced, which can be attributed to the closing or blocking of micropores by the N-groups. The CO2 adsorption on the ACF samples was via exothermic reactions and was a type of physical adsorption, where the CO2 adsorption occurred on heterogeneous surfaces. The CO2 uptakes at 1 atm and 25 °C on KOH-activated ACFs reached 2.74 mmole/g. This study observed that microporosity and surface oxygen functionalities were highly associated with the CO2 uptake, implying the existence of O-C coordination, accompanied with physical adsorption. Well cyclability of the adsorbents for CO2 adsorption was observed, with a performance decay of less than 5% over up to ten adsorption-desorption cycles.

Dynamic Adsorption and Desorption of Toluene on Carbon Nanotubes Grafted Activated Carbon Fibers

2013 ◽  
Vol 284-287 ◽  
pp. 72-76 ◽  
Author(s):  
Yu Chun Chiang ◽  
Wei Hsiang Lin
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
Physical Adsorption ◽  
Fixed Bed ◽  
Chemical Vapor Deposition Method ◽  
Active Surface Area ◽  
Activated Carbon Fibers ◽  
Adsorption And Desorption

Activated carbon fibers (ACFs) are widely used adsorbents due to their small fiber diameter, uniform pore size distribution and rapid adsorption/desorption rate. In addition, carbon nanotubes (CNTs) have received much attention recently because of their excellent mechanical and electrical properties and being candidates for adsorption. Thus, it should be highly interested as grafting CNTs onto ACFs to form a hybrid adsorbent. Therefore, the objective of this paper is to investigate the physicochemical properties of ACFs grafted with nitrogen-doped CNTs (CNs) and determine the adsorption and desorption performance of toluene vapor on this hybrid adsorbent. The chemical vapor deposition method was used for growth of CNs directly onto ACFs. The resulting materials were characterized by several techniques. Next, the adsorption breakthrough behaviors of toluene on the samples were measured in a continuous flow-type fixed-bed system. And then the temperature programmed desorption system was utilized to observe the desorption characteristics of toluene from the samples. Results show that the CNs have been grafted homogeneously onto the ACFs. The attachment of CNs on ACFs was believed to block part of the active surface area, causing the decrease in specific surface area and pore volume, but lead to the increase in microporosity. The adsorption of toluene on ACFs or the hybrid adsorbent was physical adsorption. At higher adsorption temperatures, the hybrid adsorbent could maintain high enough capacities of toluene and even exceed the performance of ACFs. Moreover, toluene could be desorbed completely from ACFs and the hybrid adsorbent up to 400 oC with the highest desorption efficiency at about 180 oC.

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.

Effect of Activated Carbon Fiber Properties on Ca2+ Removal by Capacitive Deionization

2014 ◽  
Vol 700 ◽  
pp. 281-285
Author(s):  
Qing Jun Gao ◽  
Xue Xin Liu ◽  
Lei Yuan ◽  
Kai Zhang
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Activated Carbon Fiber ◽  
Activated Carbon Fibers ◽  
Capacitive Deionization ◽  
Average Pore ◽  
Fiber Properties

Three activated carbon fibers, namely Sample A, B, and C, were used as electrodes for Ca2+ removal by capacitive deionization in this study. The physical properties of ACFs were comprehensively investigated with regard to surface area, pore volume, pore size distribution, specific capacitance, and contact angle. An internal correlation was intended to reveal between the ACF properties and their CDI performance. Pseduo-first-order adsorption kinetics model could successfully depict the Ca2+ removal with different ACF electrodes. Based on the fitting parameters, Sample B with the highest pore volume, specific capacitance, and hydrophilicity exhibited the highest equilibrium electrosorption capacity (9.977 mg-Ca2+/g-ACF). However, Sample A with the highest average pore diameter (2.4 nm) has the highest rate constant (0.074/min). Even though the abundant micropores with diameters less than 2 nm created large specific surface area in Sample C, its uptake of Ca2+ was not as good as that of Sample A.

The Effect of Oxidation Temperature on Activating Commercial Viscose Rayon-Based Carbon Fibers to Make the Activated Carbon Fibers (ACFs)

2020 ◽  
Vol 985 ◽  
pp. 171-176
Author(s):  
Le Hoang Vu ◽  
Huu Son Nguyen ◽  
Quoc Khanh Dang ◽  
Van Cuong Pham ◽  
Thai Hung Le
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
Viscose Rayon ◽  
Bet Surface Area ◽  
Activated Carbon Fibers ◽  
Toxic Chemical ◽  
Viscose Fibers ◽  
Chemical Prevention

In this work, commercial Viscose (cellulosic based precursor) rayon-based carbon fibers were oxidized to make activated carbon fibers (ACFs). Carbon fibers were made from Viscose fibers in carbonization process at 1200°C. The ultimate carbon fibers possessed carbon content above 94 mass% and fiber dimension about 8 mm. These fibers were activated to make ACFs by oxidizing gas such as steam of carbon dioxide. The experiments were conducted at temperature ranged from 800°C to 900°C with carbonic steam’s flow of 3 l.min-1. The vaporous benzene adsorbability of activated carbon fibers was then measured by Mark Bell method. The adsorbability (a) and specific surface area (ABET) of ACFs were determined. The properties of the produced ACFs were investigated and analyzed by SEM and TEM imaging. The results showed that obtained fibers have maximum benzene adsorbability of 4.58 mmol.g-1 and BET surface area reached 1357 m2.g-1. These activated carbon fibers were able to use for toxic chemical prevention equipment.

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.

CO2 adsorption capacity and kinetics in nitrogen-enriched activated carbon fibers prepared by different methods

2015 ◽  
Vol 281 ◽  
pp. 704-712 ◽  
Author(s):  
Noel Díez ◽  
Patricia Álvarez ◽  
Marcos Granda ◽  
Clara Blanco ◽  
Ricardo Santamaría ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Carbon Fibers ◽  
Co2 Adsorption ◽  
Activated Carbon Fibers ◽  
Co2 Adsorption Capacity

scholarly journals Photoconductivity of activated carbon fibers

1991 ◽  
Vol 6 (5) ◽  
pp. 1040-1047 ◽  
Author(s):  
K. Kuriyama ◽  
M.S. Dresselhaus
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Carbon Fibers ◽  
Low Temperatures ◽  
Room Temperature ◽  
High Surface ◽  
Localized States ◽  
Activated Carbon Fibers ◽  
Disordered Carbon ◽  
Increasing Temperature

The conductivity and photoconductivity are measured on a high-surface-area disordered carbon material, i.e., activated carbon fibers, to investigate their electronic properties. This material is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000–2000 m2/g. Our preliminary thermopower measurements show that the dominant carriers are holes at room temperature. The x-ray diffraction pattern reveals that the microstructure is amorphous-like with Lc ≃ 10 Å. The intrinsic electrical conductivity, on the order of 20 S/cm at room temperature, increases by a factor of several with increasing temperature in the range 30–290 K. In contrast, the photoconductivity in vacuum decreases with increasing temperature. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The recombination kinetics changes from a monomolecular process at room temperature to a bimolecular process at low temperatures, indicative of an increase in the photocarrier density at low temperatures. The high density of localized states, which limits the motion of carriers and results in a slow recombination process, is responsible for the observed photoconductivity.

Preparation and Characterization of Fibrous Cerium Oxide Templated from Activated Carbon Fibers

2005 ◽  
Vol 876 ◽  
Author(s):  
Mark Crocker ◽  
Uschi M. Graham ◽  
Rolando Gonzalez ◽  
Erin Morris ◽  
Gary Jacobs ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Cerium Oxide ◽  
Carbon Fibers ◽  
High Surface ◽  
Nitrate Solution ◽  
High Surface Area ◽  
Cerium Nitrate ◽  
Activated Carbon Fibers ◽  
Templating Method

AbstractHigh surface area cerium oxide has been prepared using a carbon templating method. Impregnation of a highly mesoporous activated carbon (Darco KB-B) with an aqueous solution of cerium nitrate, followed by carbon burn off, afforded ceria with surface area of up to 148 m2/g. According to thermogravimetric studies, ceria formation proceeds via decomposition of cerium nitrate at ca. 410 K; oxidation of the carbon template commences at the same temperature, being facilitated by the release of NO2 from the Ce compound. Use of activated carbon fibers (ACFs) as template was found to provide a simple route to fibrous cerium oxide. The lower surface areas (3 - 59 m2/g) of the resulting ceria fibers reflect the largely microporous nature of the ACFs; evidently the Ce nitrate solution is unable to penetrate their micropores. Consequently, the surface area of the ceria product is found to increase with increasing mesoporosity of the ACF template. Electron microscopy reveals that the ceria fibers are composed of highly crystalline primary particles of 5-10 nm diameter; further, the fibers display a number of interesting morphological features at the macro- and nano-scales.

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