CTAB-controlled synthesis of phenolic resin-based nanofiber aerogels for highly efficient and reversible SO2 capture

Abstract

• The structure and SO 2 capture performance of aerogels are tunable by CTAB. • High SO 2 capacity and excellent SO 2 /N 2 and SO 2 /CO 2 electivity were achieved. • A fast SO 2 adsorption rate was achieved with less than 5 min. • AG-0.15 aerogels showed good reversibility in adsorption–desorption cycles. Currently available aerogels as effective adsorption materials for capture of trace sulfur dioxide (SO 2 ) are unfavorable from the perspective of deep desulfurization technologies. Herein, four phenolic resin-based aerogels with controlled structures varying from spherical (∼1 μm) to nanofiber (∼20 nm) were prepared and characterized using hexadecyl trimethyl ammonium bromide (CATB) as a soft template. It is demonstrated that adjusting the usage amount of CTAB from 0.00 to 0.15 g could effectively regulate SO 2 adsorption capacities of phenolic resin-based aerogels. AG-0.15 nanofiber aerogel exhibited an outstanding SO 2 uptake through a swelling mechanism (10.58 mmol g −1 at 298.2 K, 1.0 bar), and displayed a very high SO 2 /N 2 selectivity (7271 at 298.2 K). Moreover, AG-0.15 nanofiber aerogel also had excellent performance for selective capture of 2000 ppm SO 2 in the mixed SO 2 /N 2 /CO 2 gases through dynamic column breakthrough experiments. Overall, phenolic resin-based nanofiber aerogels are perceived as a promising adsorbent for effective removal of trace SO 2 from flue gas.