A Microporous Organic Copolymer for Selective CO2 Capture under Humid Conditions

A cross-linked microporous organic copolymer, termed KFUPM-2, was synthesized through a Friedel-Crafts alkylation polymerization of phenothiazine, pyrrole, and p-formaldehyde in the presence of iron(III) chloride catalyst. KFUPM-2 was demonstrated to have intrinsic permanent microporosity with a Brunauer-Emmett-Teller surface area of 352 m(2) g(-1) and a high capacity (39.1 cm(3) g(-1) at 273 K and 760 Torr) and affinity (Q(st) = 34 kJ mol(-1) and CO2/N-2 selectivity of 51) toward CO2 as a result of its nitrogen-rich structure. To demonstrate its practical applicability, breakthrough measurements were performed using a gas mixture that mimicked the composition of an industrial flue gas stream (CO2/N-2 = 20/80% v/v with 91% relative humidity). Accordingly, KFUPM-2 was shown to have an ultrahigh CO2 dynamic capacity (32 cm(3) g(-1) at 298 K) in the presence of water and was demonstrated recyclable over at least 10 cycles with mild regeneration conditions needed between each cycle.