Scalable and Depurative Zirconium Metal-Organic Framework for Deep Flue-Gas Desulfurization and SO Recovery.

Deep SO removal and recovery as industrial feedstock are of importance in flue-gas desulfurization and natural-gas purification, yet developing low-cost and scalable physisorbents with high efficiency and recyclability remains a challenge. Herein, we develop a viable synthetic protocol to produce DUT-67 with a controllable MOF structure, excellent crystallinity, adjustable shape/size, milli-to-kilogram scale, and consecutive production by recycling the solvent/modulator. Furthermore, simple HCl post-treatment affords depurated DUT-67-HCl featuring ultrahigh purity, excellent chemical stability, fully reversible SO uptake, high separation selectivity (SO/CO and SO/N), greatly enhanced SO capture capacity, and good reusability. The SO binding mechanism has been elucidated by X-ray diffraction/infrared spectroscopy and DFT/GCMC calculations. The single-step SO separation from a real quaternary N/CO/O/SO flue gas containing trace SO is implementable under dry and 50% humid conditions, thus recovering 96% purity. This work may pave the way for future SO capture-and-recovery technology by pushing MOF syntheses toward economic cost, scale-up production, and improved physiochemical properties.