Trace SO 2 capture within the engineered pore space using a highly stable SnF 6 2- -pillared MOF.

Developing reliable solid sorbents for efficient capture and removal of trace sulfur dioxide (SO 2 ) under ambient conditions is critical for industrial desulfurization operations, but poses a great challenge. Herein, we focus on SNFSIX-Cu-TPA, a highly stable fluorinated MOF that utilizes SnF 6 2- as pillars, for effectively capturing SO 2 at extremely low pressures. The exceptional affinity of SNFSIX-Cu-TPA towards SO 2 over CO 2 and N 2 was demonstrated through single-component isotherms and corroborated by computational simulations. At 298 K and 0.002 bar, this material displays a remarkable gas uptake of 2.22 mmol g -1 . Among various anion fluorinated MOFs, SNFSIX-Cu-TPA shows the highest SO 2 /MF 6 2- of 1.39 mmol mmol -1 and exhibits a low Q st of 58.81 kJ mol -1 . Additionally, SNFSIX-Cu-TPA displays excellent potential for SO 2 /CO 2 separation, as evidenced by its ideal adsorbed solution theory (IAST) selectivity of 148 at a molar fraction of SO 2 of 0.01. Dynamic breakthrough curves were obtained to reveal the effective removal of trace SO 2 from simulated flue gas (SO 2 /CO 2 /N 2 ; v/v/v 0.2/10/89.8) with a high dynamic capacity of up to 1.52 mmol g -1 . Furthermore, in situ TGA demonstrated the efficient and reversible capture of 500 ppm SO 2 over 20 adsorption-desorption tests. This durable material presents a rare combination of exceptional SO 2 capturing performance, good adsorption selectivity, and mild regeneration, thus making it a good candidate for a realistic desulfurization process.