Abstract:

Porous silica nanoparticles (PSNs) with different pore structures were synthesized with cetyltrimethylammonium bromide (CTAB) as templates, tetraethoxysilane (TEOS) as silicon sources and 1,3,5-triisopropylbenzene (TPB) as pore expanding agent. TEPA-PSNs adsorbent was synthesized by physical impregnation, in which, the tetraethylpentamine (TEPA) was loaded onto the porous silica nanoparticles . The structural properties of the observed materials were characterized by SEM, TEM, FTIR and N₂ adsorption-desorption cycling experiments. Its thermal stability was characterized by thermogravimetric analysis. It was found that TEPA-functionalized PSNs with different pore structures were prepared successfully. The experimental results of CO₂ adsorption and desorption revealed that the amount of CO₂ adsorbed by the adsorbent materials increased with the increase of the TPB amount. Moreover, TEPA-PSNs-0.5 had the highest adsorption capacity of 4.70mmol/g at 75℃. The pseudo-first-order kinetic model could well predict the CO₂ adsorption process of the adsorbent. Its regenerative performance could reach 94.34% after 5 cycles. Therefore, the synthesized TEPA-functionalized porous silica had good stability and high CO₂ adsorption capacity, which was a potential material for CO₂ capture.

Key words: silica, amine functionalization, regenerative performance, kinetics, CO₂ capture

摘要：

以十六烷基三甲基溴化铵（CTAB）为模板剂，原硅酸乙酯（TEOS）为硅源，1,3,5-三异丙基苯（TPB）为扩孔剂，制备不同孔道结构的多孔二氧化硅纳米微球（PSNs），将四乙烯五胺（TEPA）通过物理浸渍法负载到PSNs上，合成TEPA-PSNs吸附剂。利用扫描电镜、透射电镜、红外光谱、N₂吸附-脱附循环实验和热重分析对材料的结构性能和热稳定性能进行表征，成功制备了具有不同孔道结构的胺基化多孔二氧化硅。对吸附剂材料进行CO₂吸脱附实验和动力学研究，结果表明：当TPB含量增多时，吸附剂材料吸附的CO₂量也随之增大，并且TEPA-PSNs-0.5在75℃时吸附量最大，达4.70mmol/g；一阶动力学模型能较好地预测该吸附剂的CO₂吸附过程；经过5次循环，其再生性能仍然高达94.34%。因此，合成的胺基化多孔二氧化硅具有高吸附量和良好稳定性，是用于二氧化碳捕集的潜在材料。

关键词: 二氧化硅, 胺基功能化, 再生性能, 动力学, 二氧化碳捕集