Porous Organic Polymers for Efficient and Selective SO₂ Capture from CO₂-rich Flue Gas

The quest for effective technologies to reduce SO₂ pollution is crucial due to its adverse effects on the environment and human health. Markedly, removing a ppm level of SO₂ from CO₂-containing waste gas is a persistent challenge, and current technologies suffer from low SO₂/CO₂ selectivity and energy-intensive regeneration processes. Here using the molecular building blocks approach and theoretical calculation, we constructed two porous organic polymers (POPs) encompassing pocket-like structures with exposed imidazole groups, promoting preferential interactions with SO₂ from CO₂-containing streams. Markedly, the evaluated POPs offer outstanding SO₂/CO₂ selectivity, high SO₂ capacity, and an easy regeneration process, making it one of the best materials for SO₂ capture. To gain better structural insights into the notable SO₂ selectivity of the POPs, we used dynamic nuclear polarization NMR spectroscopy (DNP) and molecular modelling to probe the interactions between SO₂ and POP adsorbents. The newly developed materials are poised to offer an energy-efficient and environment-friendly SO₂ separation process while we are obliged to use fossil fuels for our energy needs.