Solvent-free and one-pot synthesis of ultramicroporous carbons with ultrahigh nitrogen contents for sulfur dioxide capture

Abstract

• Porous carbon materials were synthesized by a solvent-free and one-pot route. • Rich ultramicropores and ultrahigh N contents are present in synthesized carbons. • Synthesized carbons display very high SO 2 capacities, especially at low pressures. • Impressive selectivities for SO2/CO2/N2 and good reversibility are also achieved. Recycling SO 2 from industrial tail gas is of great significance to control the environmental issues potentially induced by SO 2 emission. In the present work, porous carbons with rich ultramicropores and ultrahigh N contents (11.5–17.3 wt%) were synthesized by directly pyrolyzing the mixtures of glucose and urea at 700 ℃, without the use of any solvents. The synthesized porous carbons were characterized for porosity, morphology and elemental compositions, and also systematically investigated for SO 2 capture performance. It is found that the adsorption of SO 2 on synthesized porous carbons shows chemical behavior, owing to the strong acid-based interaction between SO 2 and pyridinic N. As consequence, the SO 2 capacities of synthesized porous carbons are very high, especially at low pressures (4.16 mmol/g at 296.2 K and 10 kPa). The synthesized porous carbons also display impressive adsorption selectivities for SO 2 /CO 2 /N 2 mixed gas, and good reversibility for SO 2 adsorption. Thus, it is believed that the synthesized porous carbons are promising candidates for selective and reversible SO 2 capture.