Rapid capture and efficient removal of low-concentration SO2 in simulated flue gas by hypercrosslinked hollow nanotube ionic polymers

Abstract

It is very challenging to design efficient adsorbent materials for SO2 capture with fast adsorption rate and with high capacity and selectivity, simultaneously. In this work, a kind of hypercrosslinked hollow nanotube ionic polymers (HNIPs) is reported for rapid capture and efficient removal of low-concentration SO2 in simulated flue gas. The HNIP-TBMB-1 exhibited very high SO2 capacity (7.2 mmol g−1) and outstanding SO2/N2 (3186) and SO2/CO2 (91) selectivity at 298 K and 1 bar. Additionally, HNIP-TBMB-1 also showed unprecedented SO2 adsorption rate and reduced the equilibrium time to 1.75 min, as well as the diffusion time constant corelated by Fick’s diffusion model was estimated to be 0.25 min−1. Dynamic breakthrough experiments further demonstrated the excellent performance of HNIP-TBMB-1 in removing 3000 ppm SO2 in simulated flue gas. In addition, HNIP-TBMB-1 showed good reversibility in adsorption–desorption cycles. The present work demonstrates that designing a HNIP material that has the special architectural feature of hollow nanotubes with inner-channels can be an effective strategy for realizing efficient, selective, and rapid SO2 capture.