Determination of the optimal pore size for improved CO2 adsorption in activated carbon fibers

Activated carbon fibers (ACFs) are one of the most promising adsorbents due to their outstanding properties, such as more exposed adsorption surface, narrower pore size distribution, fast adsorption rate and flexibility, in comparison with granular activated carbon and activated carbon powder. In this work, ACFs manufactured from various raw materials were studied and their pore structures and sulfur dioxide removal performance under dry and humid conditions were investigated. From the ACFs studied in this paper, larger surface area was found correspond to higher total pore volume and larger DA micropore diameter. In dry air, breakthrough capacity of ACFs with sulfur dioxide was found to be proportionately dependent on micropore ratio and pore size distribution. Although powdered activated carbon (PAC) showed higher breakthrough capacity, its adsorption rate was slower than ACFs due to the difference of the pore structure. The presence of water vapor in the air stream greatly increased SO2 adsorption capacities of ACFs but affected their utilization differently.

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The modification of pore size in activated carbon fibers by chemical vapor deposition and its effects on molecular sieve selectivity

Carbon ◽

10.1016/s0008-6223(97)00186-3 ◽

1998 ◽

Vol 36 (4) ◽

pp. 377-382 ◽

Cited By ~ 42

Author(s):

Yuji Kawabuchi ◽

Hidetoshi Oka ◽

Shizuo Kawano ◽

Isao Mochida ◽

Noriko Yoshizawa

Keyword(s):

Activated Carbon ◽

Chemical Vapor Deposition ◽

Pore Size ◽

Carbon Fibers ◽

Vapor Deposition ◽

Molecular Sieve ◽

Chemical Vapor ◽

Activated Carbon Fibers

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Carbon Dioxide Adsorption on Porous and Functionalized Activated Carbon Fibers

Applied Sciences ◽

10.3390/app9101977 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1977 ◽

Cited By ~ 20

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.

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