CO2 capture in different carbon materials.
ABSTRACT In this work, the CO(2) capture capacity of different types of carbon nanofibers (platelet, fishbone, and ribbon) and amorphous carbon have been measured at 26 °C as at different pressures. The results showed that the more graphitic carbon materials adsorbed less CO(2) than more amorphous materials. Then, the aim was to improve the CO(2) adsorption capacity of the carbon materials by increasing the porosity during the chemical activation process. After chemical activation process, the amorphous carbon and platelet CNFs increased the CO(2) adsorption capacity 1.6 times, whereas fishbone and ribbon CNFs increased their CO(2) adsorption capacity 1.1 and 8.2 times, respectively. This increase of CO(2) adsorption capacity after chemical activation was due to an increase of BET surface area and pore volume in all carbon materials. Finally, the CO(2) adsorption isotherms showed that activated amorphous carbon exhibited the best CO(2) capture capacity with 72.0 wt % of CO(2) at 26 °C and 8 bar.
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ABSTRACT: The objective of this research is to develop a cost-effective carbonaceous CO2 sorbent. Highly nanoporous N-doped carbons were synthesized by KOH activation of urea-modified petroleum coke. The resulting carbons show highly developed porosity and different amts. of nitrogen, depending on prepn. conditions. This series of carbons exhibits high CO2 adsorption capacities ranging from 3.69 to 4.40 mmol/g and 5.69 to 6.75 mmol/g at 25 °C and 0 °C under atm. pressure, resp. Specifically, the sample UC-650-2 prepd. at 650 °C with KOH/precursor ratio of 2 shows the highest CO2 uptake of 4.40 mmol/g at 25 °C, which is among the best of the known nitrogen-doped porous carbons. This high CO2 capture capacity is due to the synergy of the sorbent's high microporosity and nitrogen content. In addn., the CO2/N2 selectivity of the sorbent is 17, higher than that of many reported CO2 sorbents. The multi advantages of the sorbent including its easy synthesis, low cost, high CO2 uptake capacity and selectivityCarbon 01/2015; 81:465-473. · 6.16 Impact Factor
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ABSTRACT: A series of carbide-derived carbons (CDCs) with different surface oxygen contents were prepared from TiC powder by chlorination and followed by HNO3 oxidation. The CDCs were characterized systematically by a variety of means such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultimate analysis, energy dispersive spectroscopy, N2 adsorption, and transmission electron microscopy. CO2 adsorption measurements showed that the oxidation process led to an increase in CO2 adsorption capacity of the porous carbons. Structural characterizations indicated that the adsorbability of the CDCs is not directly associated with its microporosity and specific surface area. As evidenced by elemental analysis, X-ray photoelectron spectroscopy, and energy dispersive spectroscopy, the adsorbability of the CDCs has a linear correlation with their surface oxygen content. The adsorption mechanism was studied using quantum chemical calculation. It is found that the introduction of O atoms into the carbon surface facilitates the hydrogen bonding interactions between the carbon surface and CO2 molecules. This new finding demonstrated that not only the basic N-containing groups but also the acidic O-containing groups can enhance the CO2 adsorbability of porous carbon, thus providing a new approach to design porous materials with superior CO2 adsorption capacity.Nanoscale Research Letters 01/2014; 9(1):189. · 2.52 Impact Factor
- Chemical Engineering Journal 10/2014; 253:46–54. · 4.06 Impact Factor