Selective adsorption of carbon dioxide by carbonized porous aromatic framework (PAF)

A series of carbonized PAF-1s were obtained with enhanced gas storage capacities and isosteric heats of adsorption (Q(st) for short). Especially, PAF-1-450 can adsorb 4.5 mmol g(-1) CO2 at 273 K and 1 bar. Moreover, it also exhibits excellent selectivity over other gases. On the basis of single component isotherm data, the dual-site Langmuir-Freundlich adsorption model-based ideal adsorption solution theory (IAST) prediction indicates that the CO2/N-2 adsorption selectivity is as high as 209 at a 15/85 CO2/N-2 ratio. Also, the CO2/CH4 adsorption selectivity is in the range of 7.8-9.8 at a 15/85 CO2/CH4 ratio at 0 < p < 40 bar, which is highly desirable for landfill gas separation. The calculated CO2/H-2 adsorption selectivity is about 392 at 273 K and 1 bar for 20/80 CO2/H-2 mixture. Besides, these carbonized PAF-1s possess excellent physicochemical stability. Practical applications in capture of CO2 lie well within the realm of possibility.