Evaluation of CO₂ adsorption capacity of electrospun carbon fibers with thermal and chemical activation

Abstract

The use of urea was investigated as an alternative to the poisonous and expensive NH3 gas, commonly used for amination of adsorbents. First, we fabricated activated carbon nanofibers (AnFs) by electrospinning of urea‐doped polyacrylonitrile solution (N‐AnF). By increasing the activation temperature, the average specific surface area (SBET) and micropore volume (Vmicro) of pristine nFs improved from 27.3 to 300 m2/g and 0.004 to 0.13 cm3/g, respectively. Upon urea doping, both properties were further enhanced to 542 m2/g and 0.22 cm3/g, respectively. However, with chemical investigation via X‐ray photoelectron spectroscopy, we observed that the urea‐doping incorporated more of less desired quaternary‐N, along with other more basic and desirable N‐functionalities (i.e., nitrile, pyridinic, pyrrolic N) tethered. Based on the eventual CO2 adsorption results, we realized that average pore diameter (davg) is a limiting factor with regard to CO2 adsorption by AnFs; the lower the davg, the better the adsorption. Further examination via adsorption isotherm model fitting showed that CO2 molecules were homogenously collected in a monolayer pattern. However, three‐parameter model Redlich–Peterson model best fits the experimental data, suggesting that the adsorption is concentration‐driven and that it tends toward Langmuir rather than Freundlich at elevated concentration of CO2. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45534.

Improve in CO2 and CH4 Adsorption Capacity on Carbon Microfibers Synthesized by Electrospinning of PAN

“…A viable methodology for greenhouse gases capture is adsorption at mild conditions, because the adsorbents materials are easily modifiable, reusable, and adsorption is a low energetic process [2][3][4]. Some materials have been tested as adsorbents for greenhouse gases, for example, zeolites [5,6], alumina [7], mesoporous silica [8][9][10][11], and porous carbons (graphite, carbon nanotubes, and carbon fibers) [3,[12][13][14][15]. Particularly, ideal CO 2 adsorbents should comply with the following characteristics: a high specific surface area, homogenous micro-and mesopores, and many active sites on the surfaces, such as amine functional groups and basic metal oxide [13].…”

Effect of heat treatment temperature on CO2 capture of nitrogen‐enriched porous carbon fibers

“…The ACFs were treated with hydrofluoric acid to enhance the CO 2 adsorption of the fiber surface. Activated carbon nanofibers were fabricated by electrospinning of urea‐doped PAN solution . More of less‐desired quaternary‐N was incorporated in urea doping, which was also tethered with other more basic and desirable N‐functionalities.…”

Study on Adsorption Properties of Ammonium Exchanged Chabazite for CO2

“…At present, many related researches showed that MOFs had considerable potential in separating CO 2 from mixed gases such as N 2 , CH 4 , and C 2 H 2 . In addition, materials such as carbon nanotubes, activated carbon fibers, and metal oxides had also been found to have excellent gas adsorption properties in terms of CO 2 capture . However, these related materials are currently in the laboratory development stage, and the use of industrial scale still requires a long wait.…”

“…[4][5][6] In addition, materials such as carbon nanotubes, activated carbon fibers, and metal oxides had also been found to have excellent gas adsorption properties in terms of CO 2 capture. [7][8][9][10] However, these related materials are currently in the laboratory development stage, and the use of industrial scale still requires a long wait.…”