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采用浸渍方法将有机胺五乙烯六胺(PEHA)负载在介孔分子筛MCM-41的孔道表面进行改性,合成一种新型CO_2吸附剂MCM-41-PEHA。运用X射线粉末衍射法(XRD)、低温N_2吸附/脱附法(BET)和热重分析法(TGA)等手段表征了吸附剂改性前后样品的结构特征及其热物理性质,并通过固定床吸附实验,对MCM-41-PEHA吸附CO_2的性能进行研究。结果表明:经过PEHA改性后,MCM-41-PEHA吸附剂仍具有MCM-41规则均一的孔道结构;随着PEHA负载量在孔道内的增加,吸附剂的比表面积和孔体积随之相应下降。在75℃下,MCM-41-PEHA的吸附量随PEHA负载量的增加而显著上升,其中当PEHA负载量为60%(质量分数)时,吸附剂在75℃和100 kPa(CO_2分压)下吸附量最高。吸附/脱附循环稳定性实验表明:PEHA改性的MCM-41分子筛吸附剂在5次吸附/脱附循环吸附操作下,CO_2吸附量基本保持不变,吸附剂性能稳定。
The organic amine pentaethylene hexamine (PEHA) was loaded on the pore surface of mesoporous molecular sieve MCM-41 by impregnation method to synthesize a new type of CO 2 adsorbent MCM-41-PEHA. The structure characteristics and thermophysical properties of the samples before and after modification were characterized by X-ray powder diffraction (XRD), low temperature N2 adsorption / desorption (BET) and thermogravimetric analysis (TGA) Bed adsorption experiments, the performance of MCM-41-PEHA adsorbed CO_2 were studied. The results showed that MCM-41-PEHA adsorbent still has uniform MCM-41 pore structure after PEHA modification. With the increase of PEHA loading, the specific surface area and pore volume of adsorbent decreased accordingly . At 75 ℃, the adsorption amount of MCM-41-PEHA increased significantly with the increase of PEHA loading. When the PEHA loading was 60% (mass fraction), the adsorption capacity of adsorbent at 75 ℃ and 100 kPa (CO 2 partial pressure) Under the highest adsorption. Adsorption / desorption cycle stability experiments show that: PEHA modified MCM-41 molecular sieve adsorbent adsorption / desorption cycle adsorption operation, the amount of CO 2 adsorption remained unchanged, the adsorbent performance is stable.