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Small angle neutron scattering (SANS) has been applied to examine the effect of high-pressure CO2 on the structure of Wyodak coal. Significant decrease in the scattering intensities on the exposure of the coal to high-pressure CO2 showed that high-pressure CO2 rapidly gets adsorbed on the coal and reaches to all the pores in the structure. This is confirmed by strong and steep exothermic peaks observed on DSC scans during coal/CO2 interactions. In situ small angle neutron scattering on coal at high-pressure CO2 atmosphere showed an increase in scattering intensities with time suggesting that after adsorption, high-pressure CO2 immediately begins to diffuse into the coal matrix, changes the macromolecular structure of the coal, swells the matrix, and probably creates microporosity in coal structure by extraction of volatile components from coal. Significant decrease in the glass transition temperature of coal caused by high-pressure CO2 also confirms that CO2 at elevated pressures dissolve in the coal matrix, results in significant plasticization and physical rearrangement of the coal’s macromolecular structure. [ABSTRACT FROM AUTHOR]

Organic aerogels were synthesized by sol–gel polymerization of resorcinol (R) with formaldehyde (F) catalyzed by sodium carbonate (C) followed by vacuum drying. The influence of the resorcinol/sodium carbonate ratio (R/C) on the porous structure of the resultant aerogels was investigated. The nitrogen adsorption–desorption measurements show that the aerogels possess a well developed porous structure and mesoporosity was found to increase with increasing the R/C ratio. Carbon aerogels were obtained by carbonization of RF aerogels. The carbonization temperature impacts the microstructure of the aerogels by pore transformations during carbonization probably due to the formation of micropores and shrinkage of the gel structure. The results showed that a temperature of 1073 K is more effective in the development of the pore structure of the gel. Activated carbon aerogels were obtained from the CO2 activation of carbon aerogels. Activation results in an increase in the number of both micropores and mesopores, indicative of pore creation in the structure of the carbon. Activation at higher temperatures results in a higher degree of burn off and increases the pore volume and the surface area remarkably without change of the basic porous structure, pore size, and pore size distribution. [ABSTRACT FROM AUTHOR]