Activated carbon monoliths with hierarchical pore structure from tar pitch and coal powder for the adsorption of CO2, CH4 and N2

Abstract

Activated carbon monoliths with hierarchical pore structures were prepared from petroleum tar pitch and powdered coal in a low pressure foaming process with potassium hydroxide activation. The effects of the coal to tar pitch ratio and of the amount of potassium hydroxide on the stability of tar pitch during the foaming process, the product's density and the micropore structure were studied. The carbon monolith prepared with 50 %wt coal to pitch retained the shape of the foam mould, had an open-cell structure with cell widths of around 2 μm and significant microporosity that presented a BET specific surface area of 1044 m 2 •g-1. The apparent density of this structure was 0.42 g•cm-3. The adsorption capacity of the carbon monolith for CO2, N2 and CH4 were evaluated by the volumetric sorption method at pressures up to 130 kPa and by a gravimetric sorption method for pressures up to 4500 kPa. At 298 K and pressures close to 3500 kPa the adsorption capacities of the carbon monolith prepared with 50 %wt coal to pitch were 7.398 mol•kg-1 CO2, 5.049 mol•kg-1 CH4 and 3.516 mol•kg-1 N2. The sorption results suggest these activated carbon monoliths have potential as monolithic adsorbents for gas separation or storage applications.

Dicarbonyl-tuned microstructures of hierarchical porous carbons derived from coal-tar pitch for supercapacitor electrodes

“…Holes were derived from the decomposition of the carbonyl group and the self-assembly foaming process, in which gases formed by pyrolysis/gasication of active precursor molecules lead to the formation of many holes, such as in common foaming processes for preparing carbon foams. 42,43 This result is consistent with the composition characteristics of pitch cross-linked discussed above, in which the rich substituent carbonyl groups and the aromatic structures affect the fusibility of the DKCPs signicantly, and thus determines the structural properties of the pyrolyzed carbons. The HPC-DK-0.5 contains more oligomers with a lower cross-linking degree, which possesses a lower systemic viscosity and a higher plasticity.…”

Effect of rheological properties of mesophase pitch and coal mixtures on pore development in activated carbon discs with high compressive strength

“…Details of the Belsorp-BG apparatus and its operation are described in our lab's previous articles [40,41].…”

Nitrogen-Doped Carbon Foams Synthesized from Banana Peel and Zinc Complex Template for Adsorption of CO2, CH4, and N2

“…Prior to adsorption measurements the carbon foam was degassed in-situ at 473 K for 24 hrs. We have described elsewhere the operation of this apparatus to measure adsorption on carbon materials 19 , so we only include here in the Supporting Information a brief description of the BELSORP-BG measurement procedures.…”