In this study, the CO2 adsorption capacity was measured on Malaysian sub-bituminous coals in
dry and moisture equilibrated state using volumetric technique to understand its carbon
sequestration and storage potential. The CO2 adsorption capacity onto dry and wet coal samples
was performed at 300–348K and 6 MPa. Four coal specimens, namely S1, S2, S3 and S4 were
analysed by using BET, XRD and FESEM techniques before and after CO2 adsorption. The dry
S3 coal showed had the highest CO2 adsorption capacity 1.59 mmolg-1 at 300 K and 6 MPa
among all samples. FTIR spectra patterns explain this behaviour as they show an excessive
presence of hydroxyl and carboxyl functional groups in wet coal samples. The functional group
analysis of all the wet coal samples exposed to CO2 showed significantly declined adsorption
relative to their corresponding dry samples. The mineral phases were identified within all fresh
and wet exposed coal samples to CO2 through XRD analysis. The S3 coal had the highest
selectivity of CO2 over CH4 and N2 gases at pressures up to 6 MPa. The bituminous Malaysian
coal has a high affinity to adsorb CO2 in dry and wet conditions. |
