Sayari Abdelhamid, Liu Qing, Mishra Prashant
Department of Chemistry, Centre for Catalysis Research and Innovation (CCRI), University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
ChemSusChem. 2016 Oct 6;9(19):2796-2803. doi: 10.1002/cssc.201600834. Epub 2016 Sep 15.
Until recently, carbon capture and sequestration (CCS) was regarded as the most promising technology to address the alarming increase in the concentration of anthropogenic CO in the atmosphere. There is now an increasing interest in carbon capture and utilization (CCU). In this context, the capture of CO from air is an ideal solution to supply pure CO wherever it is needed. Here, we describe innovative materials for direct air capture (DAC) with unprecedented efficiency. Polyethylenimine (PEI) was supported on PME, which is an extra-large-pore silica (pore-expanded MCM-41) with its internal surfaces fully covered by a uniform layer of readily accessible C chains from cetyltrimethylammonium (CTMA ) cations. The CTMA layer plays a key role in enhancing the amine efficiency toward dry or humid ultradilute CO (400 ppm CO /N ) to unprecedented levels. At the same PEI content, the amine efficiency of PEI/PME was two to four times higher than that of the corresponding calcined mesoporous silica loaded with PEI or with different combinations of C chains and PEI. Under humid conditions, the amine efficiency of 40 wt % PEI/PME reached 7.31 mmolCO2 /g , the highest ever reported for any supported PEI in the presence of 400 ppm CO . Thus, amine accessibility, which reflects both the state of PEI dispersion and the adsorption efficiency, is intimately associated with the molecular design of the adsorbent.
直到最近，碳捕获与封存（CCS）一直被视为应对大气中人为二氧化碳浓度惊人增长的最具前景的技术。如今，人们对碳捕获与利用（CCU）的兴趣与日俱增。在此背景下，从空气中捕获二氧化碳是在任何需要的地方供应纯二氧化碳的理想解决方案。在这里，我们描述了具有前所未有的效率的用于直接空气捕获（DAC）的创新材料。聚乙烯亚胺（PEI）负载在PME上，PME是一种超大孔二氧化硅（扩孔的MCM-41），其内表面完全被一层由十六烷基三甲基铵（CTMA）阳离子提供的易于接近的碳链均匀覆盖。CTMA层在将胺对干燥或潮湿超稀二氧化碳（400 ppm CO₂/N₂）的效率提高到前所未有的水平方面起着关键作用。在相同的PEI含量下，PEI/PME的胺效率比相应的负载有PEI或不同碳链与PEI组合的煅烧介孔二氧化硅高两到四倍。在潮湿条件下，40 wt％的PEI/PME的胺效率达到7.31 mmolCO₂/g，这是在存在400 ppm CO₂的情况下任何负载PEI所报道的最高值。因此，反映PEI分散状态和吸附效率的胺可及性与吸附剂的分子设计密切相关。
