Synthesis, Characterization of Novel Porous Carbon Materials and Their Application in CO2 Capture

• Author / Creator

  Zhang, Xiaotian

• This research is aimed at developing novel, porous activated carbon materials that are used for CO2 capture. The research is mainly composed of two parts: synthesis, characterization of novel porous carbons produced via KOH activation; and evaluation of their preliminary CO2 capture performances. Various kinds of porous carbons were synthesized via KOH activation method. Through activation of multi-wall carbon nanotubes, the mechanism of pore formation was proposed. This understanding of the pore-forming mechanism also provides a good platform to investigate the effect of absorbent’s pore structures on its CO2 capture behavior. This study demonstrated the significant role of pore sizes less than 1 nm in the physisorption of CO2 molecules. Furthermore, activated carbons with ultrahigh surface area were synthesized by KOH activation of polyaniline. By studying the effect of the preheating stage, it was determined that formation of network-like nanostructure at preheating stage of the activation process is beneficial to the pore development and can lead to activated carbons with exceptionally high surface area. It is believed that this mechanism could be applied to the activation of other carbon precursors in order to achieve improved specific surface area (SSA) and micropore volume. The evaluation of the CO2 capture performances were conducted for two novel activated carbons: porous carbons derived from a liquid carbon precursor (polyethylenimine), and LiCl-incorporated activated carbons. For the porous carbons derived from polyethylenimine, they possess microporosity and rich nitrogen content. At 1 bar the CO2 uptake of the carbons was 4.9-5.7 mmol g-1 at 0 ºC. These carbons also demonstrated a selectivity of 33 for CO2 over N2 at 25 ºC and less than 1% decrease of the performance after 30 cycles. For LiCl-incorporated porous carbons, the CO2 adsorption capacity decreased after LiCl incorporation, mainly because of blocking of the small micropores. However, the increase of initial Qst after LiCl incorporation indicated a positive role of LiCl in terms of CO2 interaction with sorbent surfaces.

• Subjects / Keywords

  • CO2 capture
  • KOH activation
  • Carbon materials

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3PK07C4P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.