Polyoxometalate/Ionic Liquid Desulfurization System for Hydrogen Sulfide Removal from High-Temperature Gas Stream.

The temperature of industrial gas containing harmful H 2 S can reach hundreds of degrees. However, few processes can be used directly for H 2 S removal from industrial high-temperature gas. In this work, three polyoxometalates with different central atoms ((n-Bu 4 N) 3 VMo 12 O 40 , (n-Bu 4 N) 3 PMo 12 O 40 , and (n-Bu 4 N) 4 [α-SiMo 12 O 40 ]) were synthesized and dissolved in four ionic liquids (Bmim]Cl, [Bmim]HCO 3 , [Bmim]Mes, or [Bmim]OAc) for H 2 S removal from high-temperature (90-180 °C) gases. The result showed that (n-Bu 4 N) 3 VMo 12 O 40 /[Bmim]OAc exhibited the optimal desulfurization performance, maintaining more than 98.6% desulfurization efficiency within 10 h. The reacted desulfurization solution can be regenerated by blowing air. FT-IR and XPS results show that both the central atom V and the coordination atom Mo of the polyoxometalate are involved in the oxidation of H 2 S; after the regeneration by introducing air, V(+IV) and Mo(+IV) recovered to V(+V) and Mo(+VI), respectively. Our research shows that (n-Bu 4 N) 3 VMo 12 O 40 /[Bmim]OAc is an efficient, easy-to-regenerate, and suitable high-temperature gas desulfurization solution.