Preparation of ionic organic porous polymer and its coupled desulfurization and decarbonization properties in flue gas

Cost-effective capture of SO2 and CO2 from flues gas is still an ongoing challenge to the global ecological environment. Adsorption separation technology with low energy consumption is a promising gas capture technology but porous adsorbents with high capacity, high selectivity and good stability are very scarce. Herein a stable porous organic polymer (named PPN-1) by the reaction of isatin with triptycene under superacidic condition was synthesized. The ionic porous organic polymer was achieved by quaternization of PPN-1 with methyl iodide and then treated with KOH solution for exchange of I- with OH- to obtain PPN-1-OH. PPN-1 and PPN-1-OH had high affinity toward SO2 and CO2 due to their suitable BET surface areas, considerable microporous structures and abundant electron-rich nitrogen and oxygen atoms. Interestingly, PPN-1-OH possessed an ultra-high SO2 capture performance (13.09mmol/g) at 0.1MPa and 298K, which exceeded previous reported porous adsorbents. Moreover, an excellent SO2 dynamic adsorption capacity of 1.81mmol/g and SO2/CO2 selectivity (211) in ternary gas mixture (SO2/CO2/ N2=0.2/9/90.8, v/v/v) was achieved in PPN-1-OH based on column breakthrough experiments. The theory simulation revealed that the introduction of hydroxyl groups into the micropore channels of PPN-1-OH could significantly enhance the interaction between SO2 and PPN-1-OH and improved the SO2 capture capacity and selectivity. © 2023 Chemical Industry Press. All rights reserved.