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周 刚,杨思奥,王凯丽,等. TEPA改性Cu-BTC@SiO2复合气凝胶制备及其捕集CO2特性研究[J]. 煤炭科学技术,2024,52(7):235−247. doi: 10.12438/cst.2023-1044
引用本文: 周 刚,杨思奥,王凯丽,等. TEPA改性Cu-BTC@SiO2复合气凝胶制备及其捕集CO2特性研究[J]. 煤炭科学技术,2024,52(7):235−247. doi: 10.12438/cst.2023-1044
ZHOU Gang,YANG Siao,WANG Kaili,et al. TEPA modification Cu-BTC@SiO2 preparation of composite aerogel and its CO2 capture characteristics[J]. Coal Science and Technology,2024,52(7):235−247. doi: 10.12438/cst.2023-1044
Citation: ZHOU Gang,YANG Siao,WANG Kaili,et al. TEPA modification Cu-BTC@SiO2 preparation of composite aerogel and its CO2 capture characteristics[J]. Coal Science and Technology,2024,52(7):235−247. doi: 10.12438/cst.2023-1044

TEPA改性Cu-BTC@SiO2复合气凝胶制备及其捕集CO2特性研究

TEPA modification Cu-BTC@SiO2 preparation of composite aerogel and its CO2 capture characteristics

  • 摘要: 在“碳达峰、碳中和”这一国家重大战略背景下,CO2捕集已经成为当前重大科技发展方向。固体吸附剂吸附法在CO2的捕集过程中应用广泛,其中SiO2气凝胶具有成本低、合成方法灵活、分离效率高、表面易修饰等优点。然而,SiO2气凝胶材料也存在CO2/N2吸附选择性低,CO2吸附容量有待继续提高等缺陷。为解决上述问题,制备了一种Cu-BTC@SiO2复合气凝胶CO2吸附材料。首先,利用扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)和氮气吸脱附测试对材料表面化学和孔隙结构进行了系统表征。然后,通过二氧化碳吸附测试对其CO2吸附量、选择性吸附、循环吸附进行了研究。最后,采用理论与试验研究结合的方法,对吸附剂的CO2吸附动力学进行了研究。结果表明:Cu-BTC与SiO2气凝胶具有结构协同作用,与Cu-BTC复合后的SiO2气凝胶不会改变材料的Si-O-Si骨架结构,同时可以保持Cu-BTC的晶体结构不受到损坏。复合材料具有726.431 m2/g的高比表面积,570.781 m2/g的微孔比表面积和0.184 cm3/g的高微孔体积。负载四乙烯五胺(TEPA)后CO2吸附量高达3.20 mmol/g,CO2/N2选择性吸附系数为40.8,循环10次CO2吸附循环,吸附容量仅下降14%,提高了SiO2气凝胶材料的CO2吸附容量和吸附选择性。Avrami分数动力学模型对吸附试验结果拟合相关系数为0.99,且Avrami指数nA为1.9表明吸附剂对CO2的吸附是非均质的多层吸附,既有物理吸附又有化学吸附,且以物理吸附为主。利用具有丰富微孔结构的金属有机骨架材料Cu-BTC与SiO2气凝胶进行复合,使复合材料具有分级微/介孔结构,通过增强分子间作用力(范德华力)来增强材料对CO2的物理吸附;使用TEPA对材料进行浸渍改性,利用有机胺和酸性气体之间的酸碱相互作用来增强材料对CO2的化学吸附。

     

    Abstract: Under the dual strategic background of “carbon peaking and carbon neutrality”, CO2 capture has become an important task at present. Solid adsorbent adsorption is widely used in CO2 capture process, among which SiO2 aerogel has the advantages of low cost, flexible synthesis method, high separation efficiency, easy surface modification, etc. However, SiO2 aerogel materials also have some defects, such as low CO2/N2 adsorption selectivity and CO2 adsorption capacity to be further improved. To address the above issues, this article has prepared a Cu-BTC@SiO2 Composite aerogel CO2 adsorption material. Firstly, the surface chemistry and pore structure were systematically characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption and desorption tests. Then, the CO2 adsorption capacity, selective adsorption, and cyclic adsorption were studied through carbon dioxide adsorption testing. Finally, a combination of theoretical and experimental research was used to study the CO2 adsorption kinetics of the adsorbent. The results show that the SiO2 aerogel compounded with Cu BTC has a high specific surface area of 726.431 m2/g, a specific surface area of 570.781 m2/g, and a high microporous volume of 0.184 cm3/g. After loading tetraethylenepentamine(TEPA), the adsorption capacity of CO2 is up to 2.95 mmol/g, and the selective adsorption is 40.8, after 10 cycles of CO2 adsorption, the adsorption capacity decreased slightly. Therefore, TEPA-modified Cu-BTC@SiO2 composite aerogels can significantly improve the CO2 adsorption performance of SiO2 aerogels. The metal organic framework material Cu BTC with rich micropore structure is compounded with SiO2 aerogel, and is prepared by the sol gel method Cu-BTC@SiO2 Composite aerogel to make the composite have hierarchical micro/mesoporous structure and enhance the physical adsorption of CO2 by enhancing the intermolecular force (van der Waals force); The material is impregnated with TEPA, and the chemical adsorption of CO2 is enhanced by acid-base interaction between organic amine and acid gas.

     

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