ZIFs@SBA-15复合材料的设计合成及吸附分离密闭空间低浓度CO2的研究

In order to ensure the human safety, it is essential to control the CO2 concentration in confined space. The development of processes based on solid adsorbents has been proposed as alternative separation technologies for CO2 capture. In this proposal, Zeolite imidazolate frameworks (ZIFs)@SBA-15 hybrid material is prepared by using SBA-15 as a matrix. The growth of ZIFs inside the pores of SBA-15 is expected to enhance the adsorption capacity and selectivity of CO2. Meanwhile, SBA-15 serves as a shell, which is beneficial to improve the stability of the adsorbent. The study is conducted to explore a new way to synthesize adsorbents with good performance through adjusting the pore size and surface properties of support. The composition and textural properties of the as-prepared materials would be examined by XRD, N2 adsorption-desorption isotherms, element analysis and SEM et al. According to the results, the novel and efficient method of preparing the ZIFs@SBA-15 adsorbent will be developed. Furthermore, the mechanism of ZIFs growth inside the pores of SBA-15 will be investigated, and the relationships between composition, structure and the CO2 adsorption performance of the hybrid material will also be explored. The results obtained in this project may develop a new theory for optimization design of ZIFs@SBA-15 adsorbent, enrich the species of functional mesoporous material, and thus establish theoretical foundation for the development of highly efficient CO2 adsorbent material.

控制密闭空间CO2浓度是保障人员生命安全的必要措施。采用多孔材料吸附脱除CO2是一种成熟的方法，其关键在于高效吸附材料的研究。本项目拟设计合成沸石咪唑酯骨架（ ZIFs ）@SBA-15复合吸附材料，利用ZIFs所含的碱性有机配体，提高吸附材料的CO2吸附量和选择性；利用SBA-15材料的“保护作用”，提高吸附材料的稳定性和机械强度。通过调变SBA-15载体的孔尺寸和表面性质，合成系列ZIFs@SBA-15复合材料，利用各种表征、测试手段分析材料的组成、结构和CO2吸附性能；研究载体性质对ZIFs“限域”生长的影响机制；揭示吸附材料的“构效关系”。本项目的顺利实施，将形成ZIFs@SBA-15吸附材料的优化设计理论，丰富功能化介孔材料的种类，为开发高效CO2吸附材料奠定理论基础。

低浓度CO2吸附分离技术在密闭空间生命支持、温室气体减排等领域得到了广泛的应用，其关键在于高效吸附材料的研究与开发。沸石咪唑酯骨架结构材料(ZIFs)在室温下CO2吸附分离性能良好，且有机配体不易流失。然而，限于ZIFs材料普遍存在颗粒尺寸小、机械强度低等缺点，直接将上述ZIFs材料用于低浓度CO2脱除尚有诸多困难。本项目通过不同方法，合成了一系列ZIFs复合材料，考察了载体材料孔结构及表面性质对固载ZIFs的影响；研究了合成条件对复合材料的孔结构及ZIFs的结晶度、负载量、稳定性等的影响规律；分别以静态法和动态法研究上述吸附材料的CO2吸附量、选择性、吸/脱附速率、循环使用寿命等性能，通过与ZIFs复合材料的组成和结构物性相关联，揭示了材料的“构效关系”，形成了ZIFs复合吸附材料的优化设计理论，为高效CO2吸附材料的制备提供设计原则。实验结果表明：ZIFs复合材料对CO2的吸附量较纯ZIFs略有下降，但吸附速率较快，选择性较高，循环使用性能良好。吸附为放热过程，Avrami吸附模型可较好地模拟ZIFs复合材料对CO2的吸附行为。在本项目研究过程中，在化工主流期刊发表标注本项目号的论文9篇，授权国家发明专利3件，参加学术会议4次，培养硕士研究生4名。