Insights into CO2 and CH4 adsorption by pristine and aromatic amine-modified periodic mesoporous phenylene-silicas

The synthesis and characterization of pristine and amine-functionalized periodic mesoporous phenylene-silicas having different pore sizes are reported. We explore the potential of these materials for CO2/CH4 separation, by studying the adsorption of pure CO2 and pure CH4 gases. The aminated periodic mesoporous phenylene-silica with the smallest pore size is the best adsorbent to CO2, presenting a Henry’s constant of 0.56 mol·kg-1·bar-1 at 35 ºC. However, the corresponding Henry’s constant for CH4 is extremely low (0.06 mol·kg-1·bar-1 at 35 ºC). It is observed a direct correlation between the % of T2SMP silanols species and the values of the Henry’s constants, which may be used to theoretically predict experimental CO2 Henry’s constants of potential adsorbents.