The aim of this project is the design, synthesis and characterisation of porous carbon structures capable of the selective capture of carbon dioxide (CO2) from the exhaust gases of coal and gas post-combustion power stations. In such systems, the fossil fuel is burnt in an air environment producing CO2 as just one of a multi-component flue gas. This flue gas is expected to contain nitrogen and water among other constituents. It is at ambient pressures and temperatures of ≥323 K. Successful capture materials should have highly microporous structures, rapid sorption kinetics and be capable of repeated sorption/desorption cycles. To develop highly microporous carbon sorbents a range of porous materials have been synthesised using chemical and physical activation of precursors obtained through top down and bottom up approaches. Porosity has also been achieved in precursors through the controlled use of graphene exfoliation, melamine-formaldehyde resin aerogel formation, soft templates, controlled carbonisation and synthesis of microporous organic polymers. The role of nitrogen dopants (N-dopants) within the CO2 sorbent materials has also been investigated. To increase understanding and tune the sorbents performance, porous carbon structures have been synthesized containing: pyridine, pyrrole, quaternary and triazine nitrogen groups. Characterisation was achieved using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, transmission electron microscopy X-ray diffraction, thermogravimetric analysis and nitrogen (N2) isotherms at 77 K. CO2 sorption analysis was carried out using volumetric and gravimetric analysis. The influence of N-dopants on the adsorbate-adsorbent interaction is characterised using CO2 volumetric isotherms, isosteric heats of adsorption and CO2/N2 selectivity analysis.
|University College London (University of London)
|Electronic Thesis or Dissertation
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