Highly Selective Mixed-Matrix Adsorbents Embedded with Anion-Pillared Microporous Materials and Poly(ionic liquid)s toward Sulfur Dioxide Capture

SO2 emission has become an important issue due to its harmful impact on human health and the ecological environment. Adsorption separation is an energy-efficient technology to capture SO2, but it suffers from competitive adsorption of CO2. Here, we present a strategy to improve the separation performance of porous adsorbents through the fabrication of mixed-matrix adsorbents. By the introduction of a perm-selective polymer (P(D[VImC6]Br)) as the matrix to enclose anion-pillared microporous materials (SIFSIX-3-Ni), CO2 molecules were selectively blocked, while the SO2 molecules could still permeate the polymer matrix and access the porous particles of SIFSIX-3-Ni. As a result, a high SO20.2%/CO210% uptake ratio of 32 at 298 K and 1 bar and a high SO2 uptake capacity of 0.67 mmol g–1 at 0.002 bar were achieved for the mixed-matrix adsorbents of SIFSIX-3-Ni@PIL-1/1. The strategy for fabricating a perm-selective matrix around the porous adsorbent particles to improve the adsorption performance is generally applicable to other porous adsorbents.