Synthesis of Guanidinium-Based Poly(ionic liquids) with Nonporosity for Highly Efficient SO2 Capture from Flue Gas

Because of considerable adsorption capacities of competitive gases N 2 and CO 2, many kinds of porous materials suffer from unsatisfied SO 2 /CO 2 and SO 2 /N 2 selectivities and thus hardly achieve deep removal of SO 2 from flue gas. Herein, a novel type of guanidinium-based poly(ionic liquid) with the feature of nonporosity was designed and prepared through a facile copolymerization procedure. It is very attractive that nonporous guanidinium-based poly(ionic liquids) P([allyl-TMG]Br-DVB) by polymerization of (allyl-tetramethylguanidine)bromide with divinylbenzene had almost excluded the adsorption of N 2 (0.01 mmol g –1 ) and CO 2 (0.07 mmol g –1 ) but showed very high SO 2 capacity (9.79 mmol g –1 ) at 25 °C and 1 bar. The high selectivities of SO 2 /CO 2 (452) and SO 2 /N 2 (2294) were accordingly obtained. Furthermore, column breakthrough experiments confirmed the excellent separation performance of P([allyl-TMG]Br-DVB) in deeply eliminating 2000 ppm SO 2 in the mixture of SO 2 /N 2 /CO 2 . The employment of nonporous poly(ionic liquids) as efficient adsorbents is an effective strategy for the deep removal of SO 2 from flue gas.