Enhanced CO2 Adsorption on Activated Carbon Fibers Grafted with Nitrogen-Doped Carbon Nanotubes

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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Effects of surface chemical properties of activated carbon fibers modified by liquid oxidation for CO2 adsorption

Applied Surface Science ◽

10.1016/j.apsusc.2015.06.046 ◽

2015 ◽

Vol 353 ◽

pp. 158-164 ◽

Cited By ~ 34

Author(s):

Byong Chol Bai ◽

Eun Ae Kim ◽

Chul Wee Lee ◽

Young-Seak Lee ◽

Ji Sun Im

Keyword(s):

Activated Carbon ◽

Carbon Fibers ◽

Co2 Adsorption ◽

Chemical Properties ◽

Activated Carbon Fibers ◽

Surface Chemical

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Adsorption of nitrate onto nitrogen-doped activated carbon fibers prepared by chemical vapor deposition

Korean Journal of Chemical Engineering ◽

10.1007/s11814-018-0151-4 ◽

2018 ◽

Vol 35 (12) ◽

pp. 2468-2473 ◽

Cited By ~ 5

Author(s):

Pyunghwa Yoo ◽

Yoshimasa Amano ◽

Motoi Machida

Keyword(s):

Activated Carbon ◽

Chemical Vapor Deposition ◽

Carbon Fibers ◽

Vapor Deposition ◽

Chemical Vapor ◽

Activated Carbon Fibers ◽

Nitrogen Doped

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Selective and enhanced CO2 adsorption on fluorinated activated carbon fibers

Chemical Physics Letters ◽

10.1016/j.cplett.2020.137909 ◽

2020 ◽

Vol 758 ◽

pp. 137909 ◽

Cited By ~ 1

Author(s):

Hironori Sugiyama ◽

Yoshiyuki Hattori

Keyword(s):

Activated Carbon ◽

Carbon Fibers ◽

Co2 Adsorption ◽

Activated Carbon Fibers

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.72 ◽

2013 ◽

Vol 284-287 ◽

pp. 72-76 ◽

Cited By ~ 1

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.

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