Abstract:

Cost-effective capture of SO₂ and CO₂ from flues gas is still an ongoing challenge to the global ecological environment. Adsorption separation technology with low energy consumption is a promising gas capture technology but porous adsorbents with high capacity, high selectivity and good stability are very scarce. Herein a stable porous organic polymer (named PPN-1) by the reaction of isatin with triptycene under superacidic condition was synthesized. The ionic porous organic polymer was achieved by quaternization of PPN-1 with methyl iodide and then treated with KOH solution for exchange of I^- with OH^- to obtain PPN-1-OH. PPN-1 and PPN-1-OH had high affinity toward SO₂ and CO₂ due to their suitable BET surface areas, considerable microporous structures and abundant electron-rich nitrogen and oxygen atoms. Interestingly, PPN-1-OH possessed an ultra-high SO₂ capture performance (13.09mmol/g) at 0.1MPa and 298K, which exceeded previous reported porous adsorbents. Moreover, an excellent SO₂ dynamic adsorption capacity of 1.81mmol/g and SO₂/CO₂ selectivity (211) in ternary gas mixture (SO₂/CO₂/N₂=0.2/9/90.8, v/v/v) was achieved in PPN-1-OH based on column breakthrough experiments. The theory simulation revealed that the introduction of hydroxyl groups into the micropore channels of PPN-1-OH could significantly enhance the interaction between SO₂ and PPN-1-OH and improved the SO₂ capture capacity and selectivity.

Key words: adsorption separation, sulfur dioxide, carbon dioxide, ionic porous organic polymer, carbon capture

摘要：

高效经济地消除燃煤烟气中的SO₂和CO₂对生态环境具有重要意义，但开发具有高捕集能力、高选择性和良好稳定性的吸附剂仍然是一个挑战。本文通过靛红与芳香族单体（三蝶烯）在超酸性条件下反应得到了性质稳定的有机多孔聚合物吸附剂PPN-1，并对PPN-1季胺化以及离子交换获得离子型多孔聚合物PPN-1-OH。由于两种有机多孔吸附剂拥有合适的BET表面积、丰富的微孔孔道以及大量的富电子基团，PPN-1和PPN-1-OH对SO₂和CO₂具有很强的亲和力。尤其是离子型有机多孔聚合物PPN-1-OH显示出超高的静态吸附能力，在298K、0.1MPa下其SO₂的吸附量高达13.09mmol/g，超过了此前报道的多孔材料。基于瞬时吸附速率，理想吸附溶液理论模拟和固定床穿透实验的研究证明PPN-1-OH具有卓越的SO₂动态吸附容量和选择性。在三组分混合气体(SO₂/CO₂/N₂=0.2/9/90.8，体积比)动态固定床穿透实验中，PPN-1-OH的SO₂吸附量高达1.81mmol/g，SO₂/CO₂选择性突破211。理论分析表明PPN-1-OH微孔孔道内大量的羟基基团能显著增强骨架与SO₂之间的结合力，有效地提高吸附容量和选择性。

关键词: 吸附分离, 二氧化硫, 二氧化碳, 离子型有机多孔聚合物, 碳捕集