Hybrid solid CO₂ adsorbents prepared from commercially available silica and polyethylenimine (PEI) are potential candidate for large scale carbon capture applications. In this study, the effect of the silica support structure and morphology on the CO₂ adsorption capacity of the adsorbent was investigated. Two series of silica supports with distinct morphology, i.e. granular and microspherical, available from PQ-Corp., and well defined surface area, pore diameter, and pore volume were loaded with branched PEI. The CO₂ adsorption characteristics of these adsorbents were measured using thermogravimetric analysis (TGA). The increase in PEI loading on the porous silica caused a significant decrease in surface area and pore volume. At a certain loading level, the pores were completely filled with PEI, and the CO₂ diffusion was hindered resulting in lower adsorption capacity and amine efficiency. With granular silicas, supports having an average pore diameter greater than about 240 Å performed best. However, once this threshold in pore diameter was passed, the adsorption capacity did not improve much further. For microspherical silica supports this threshold was around 300 Å. For supports with a same pore volume, the ones with a larger pore diameter had higher CO₂ adsorption capacity, even if their surface area was lower. This difference was mainly due to the easier diffusion of CO₂ into the pores, because the phenomenon was more pronounced at a low adsorption temperature (25 °C), where diffusion control was most significant.

由可商购获得的二氧化硅和聚乙烯亚胺（PEI）制备的混合固体CO ₂吸附剂是大规模碳捕获应用的潜在候选者。在这项研究中，研究了二氧化硅载体结构和形态对吸附剂对CO ₂吸附能力的影响。可从PQ-Corp。购得的具有不同形态的两个系列的二氧化硅载体，即颗粒状和微球形的，以及定义明确的表面积，孔径和孔体积的支链PEI被装载。一氧化碳₂使用热重分析（TGA）测量这些吸附剂的吸附特性。PEI在多孔二氧化硅上的负载增加导致表面积和孔体积显着减少。在一定的负载水平下，孔被PEI完全填充，并且CO _2的扩散受到阻碍，导致较低的吸附能力和胺效率。对于粒状二氧化硅，平均孔径大于约240的载体表现最佳。但是，一旦超过该孔径的阈值，吸附能力就不会进一步提高。对于微球形二氧化硅载体，该阈值约为300。对于孔径相同的载体，孔径较大的载体具有较高的CO _2。吸附能力，即使它们的表面积较小。这种差异主要是由于CO ₂更容易扩散到孔中，因为这种现象在较低的吸附温度（25°C）时更为明显，在该温度下扩散控制最为明显。