Direct Evidence of Carbon Dioxide Sorption on Argonne Premium Coals Using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy

摘要

The direct interaction between CO_2 and two Argonne Premium Coals [Pocahontas No.3(low-volatile bituminous)and Beulah-Zap(lignite)] was probed by use of attenuated total reflectance-Fourier transform infrared(ATR-FTIR)spectroscopy at 328 K and pressures up to 8.0 MPa.Sorbed CO_2 on Argonne Coals was detected at 2335 cm~(-1)for Beulah-Zap coal and 2332 cm~(-1)for Pocahontas No.3 coal.The energy of adsorption(18.8-20.5 kJ/mol),estimated from the Langmuir equation,was consistent with physisorption.The spectral data indicated that only one type of site was available for sorption.No evidence could be found for specific interactions between CO_2 and oxygen functional groups in the coals.The CO_2-coal sorption isotherm was derived without estimating the CO_2 compressibility and adsorbed layer density,both of which are needed in manometric techniques.