Department of Chemical and Biomolecular Engineering, KAIST, Daejeon, 34141, Republic of Korea.
ChemSusChem. 2017 Jun 9;10(11):2518-2526. doi: 10.1002/cssc.201700398. Epub 2017 May 16.
Poly(ethyleneimine) (PEI)/silica has been widely studied as a solid adsorbent for post-combustion CO capture. In this work, a highly macroporous silica (MacS), synthesized by secondary sintering of fumed silica, is compared with various mesoporous silicas with different pore structures as a support for PEI. The silicas with large pore diameter and volume enabled high CO adsorption kinetics and capacity, because pore occlusion by the supported PEI was minimized. The steam stability of the silica structures increased with the silica wall thickness owing to suppressed framework ripening. The silicas with low steam stability showed rapid leaching of PEI, which indicated that the PEI squeezed out of the collapsed silica pores leached more readily. Consequently, MacS that had an extra-large pore volume (1.80 cm g ) and pore diameter (56.0 nm), and a thick wall (>10 nm), showed the most promising CO adsorption kinetics and capacity as well as steam stability.
聚（乙撑亚胺）（PEI）/二氧化硅已被广泛研究作为后燃烧 CO 捕获的固体吸附剂。在这项工作中，通过二次烧结气相二氧化硅合成的大孔二氧化硅（MacS）与具有不同孔结构的各种介孔二氧化硅作为 PEI 的载体进行了比较。具有大孔径和大孔体积的二氧化硅可以实现高 CO 吸附动力学和容量，因为负载的 PEI 的孔阻塞最小化。由于抑制了骨架熟化，二氧化硅结构的蒸汽稳定性随二氧化硅壁厚度的增加而增加。蒸汽稳定性低的二氧化硅显示出 PEI 的快速浸出，这表明从塌陷的二氧化硅孔中挤出的 PEI 更容易浸出。因此，具有特大孔体积（1.80cm ³/g）和孔径（56.0nm）以及厚壁（>10nm）的 MacS 表现出最有前途的 CO 吸附动力学和容量以及蒸汽稳定性。
