A synergy of DUT-67(Zr)@AFP with hierarchical pores and amines to remove trace SO from flue gas.

The recovery and reduction of SO₂ face significant challenges in balancing separation performance with renewability and stability. Herein we have successfully designed and prepared a novel composite material (DUT-67(Zr)@AFP) with a hierarchical porous structure and rich amine groups. The equilibrium adsorption results indicate that DUT-67(Zr)@AFP has excellent SO uptake (208 mL/g) and SO/CO selectivity (469) with outstanding comprehensive separation performance and excellent renewability, establishing a new benchmark. Additionally, due to the synergistic contribution of hierarchical pores and amine groups, the trace SO uptake (2000 ppm) was increased by 180 % (23 mL/g), while the SO adsorption time (2.8 min) was reduced by 35 % relative to DUT-67(Zr) (8 mL/g and 4.3 min). Theoretical calculations combined with in-situ spectra unveiled the adsorption mechanism. Furthermore, breakthrough experiments also confirmed that DUT-67(Zr)@AFP achieved complete separation of N/CO/SO and possesses an SO breakthrough uptake of 22 mL/g, far exceeding the parent DUT-67(Zr) (11 mL/g). Besides, DUT-67(Zr)@AFP can also exist stably in harsh environments, proving superb structural stability. Thus, the benchmark alliance of excellent adsorption and separation performances and excellent regeneration and superb structural stability in DUT-67(Zr)@AFP with a hierarchical porous structure and rich amine groups has revealed its enormous prospect in this puzzling industrial separation.