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 CO2, many kinds of porous materials suffer from unsatisfied SO2/CO2 and SO2/N-2 selectivities and thus hardly achieve deep removal of SO2 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 CO2 (0.07 mmol g(-1)) but showed very high SO2 capacity (9.79 mmol g(-1)) at 25 degrees C and 1 bar. The high selectivities of SO2/CO2 (452) and SO2/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 SO2 in the mixture of SO2/N-2/CO2. The employment of nonporous poly(ionic liquids) as efficient adsorbents is an effective strategy for the deep removal of SO2 from flue gas.

Automated summary

A novel type of guanidinium-based poly(ionic liquid) with nonporosity was designed and prepared, showing high SO2 capacity and selectivity while excluding adsorption of CO2 and N-2. The nonporous poly(ionic liquids) demonstrated excellent performance in removing SO2 from flue gas.