Kim Chaehoon, Choi Woosung, Choi Minkee
Department of Chemical and Biomolecular Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea.
ACS Appl Mater Interfaces. 2019 May 8;11(18):16586-16593. doi: 10.1021/acsami.9b02831. Epub 2019 Apr 29.
Amine-containing solids are promising adsorbents for CO capture, but they suffer from irreversible poisoning by the highly acidic SO in flue gas. Here, we demonstrate a facile strategy to inhibit SO poisoning. We first prepared an amine-containing adsorbent by impregnating polyethyleneimine (PEI) into porous silica. The PEI located at the external surface of the adsorbent was selectively alkylated with epoxide so that amines were fully converted to tertiary amines. As opposed to that onto primary and secondary amines, SO adsorption onto tertiary amines is fully reversible. Therefore, during the flue gas adsorption, SO is reversibly captured by the tertiary-amine-rich layer and then desulfurized CO is adsorbed onto PEI beneath this layer. The resultant adsorbent showed insignificant loss of CO adsorption capacity (8.52%) even after 1000 CO adsorption-desorption cycles in the presence of 50 ppm SO, whereas conventional PEI/silica showed severe capacity loss (65.1%) due to irreversible SO poisoning.
含胺固体是用于捕获二氧化碳的有前景的吸附剂，但它们会因烟气中高酸性的二氧化硫而遭受不可逆中毒。在此，我们展示了一种抑制二氧化硫中毒的简便策略。我们首先通过将聚乙烯亚胺（PEI）浸渍到多孔二氧化硅中来制备含胺吸附剂。位于吸附剂外表面的PEI用环氧化物进行选择性烷基化，使得胺完全转化为叔胺。与伯胺和仲胺不同，二氧化硫在叔胺上的吸附是完全可逆的。因此，在烟气吸附过程中，二氧化硫被富含叔胺的层可逆捕获，然后脱硫后的二氧化碳被吸附到该层下方的PEI上。即使在存在50 ppm二氧化硫的情况下经过1000次二氧化碳吸附 - 解吸循环后，所得吸附剂仍显示出微不足道的二氧化碳吸附容量损失（8.52%），而传统的PEI/二氧化硅由于不可逆的二氧化硫中毒而显示出严重的容量损失（65.1%）。
