An optimal trapdoor zeolite for exclusive admission of CO2 at industrial carbon capture operating temperatures.

High purity molecular trapdoor chabazite with an optimal Si/Al ratio (1:9) was prepared from fly ash. Gas adsorption isotherms and binary breakthrough experiments show dramatically large selectivities for CO2 over N2 and CH4, which are the highest among physisorbents at operating temperatures suitable for postcombustion carbon capture and natural gas separations.