具有规则层状孔道结构的蒙脱土柱撑杂化炭膜可控制备研究

Today, how to improve the ratio of performance to price and break through the trade-off between permeability and selectivity has restricted the development of carbon membranes for gas separation. In this study, the precursors are designed and modificated by intercalation based on the microscopic scale and the supported structure of montmorillonite. Pore structure and size of carbon membranes have been controlled and constructed in microscopic level. The preparation of carbon hybrid membranes supported montmorillonite with regularly layered nanopores are proposed. The carbon membrane with these pore structure will reduce the resistance of gas permeation and improve the recognition ability of molecular size. Therefore, the trade-off between permeability and selectivity is solved. Mathematical model is established to simulate and reveal the relation of pore structure and gas separation performance. Furthermore, the basic theory of controllable preparation of carbon membranes is preposed. The results of this study will enrich the theory of preparation technology for carbon membranes, especially in the face of optimal pore structure and separation performance. Also, the study has scientific significance and practical application to improve the mechanical properties, and decrease the cost, and promote the industrialization of carbon membranes.

当前，如何提高性价比，突破渗透性和选择性之间的矛盾关系，已成为制约气体分离炭膜发展的关键问题。本课题从微观尺度出发，利用蒙脱土的柱撑结构，通过插层复合对前驱体进行设计和改性，在微介观层面上对炭膜精细孔道结构和尺度进行调控和构建，提出了制备具有规则纳米层状孔道结构的蒙脱土柱撑杂化炭膜。具有这种孔道结构的炭膜，减小了气体渗透阻力，提高了对分子大小的识别能力，从而解决渗透性和选择性之间的矛盾。通过建立数学模型模拟炭膜孔道结构和分离过程，揭示炭膜孔结构和气体分离性能的内在关系，提出炭膜可控制备的基本理论。本研究工作的成果可丰富炭膜制备技术的基础理论，特别是优化孔道结构和提高分离性能方面；同时对增强炭膜，降低成本，促进炭膜产业化应用，具有重要的科学意义和实际应用价值。

炭膜是一种高性能膜分离材料，但性价比低及无法突破渗透性和选择性的矛盾关系成为制约其产业化应用的关键问题。本课题设计并改性了一系列绿色环保、价廉易得的天然聚合物作为炭膜前驱体，采用插层复合法成功制备出无缺陷的蒙脱土柱撑杂化炭膜；研究了各种前驱体的热解机理和成膜性，为杂化炭膜的制备提供重要依据；采用壳聚糖为前驱体，自制阳离子试剂为插层剂制备的柱撑杂化炭膜，蒙脱土在基质中分散均匀，炭化后蒙脱土由二维层状结构转化为三维层状结构，有效的保护了前驱体的骨架和晶型，避免其在炭化时过度塌陷，改善了炭膜蠕虫状孔道结构的规整性，得到孔结构分布均匀的杂化炭膜。采用壳聚糖/淀粉共混材料作为炭膜前驱体制备的蒙脱土柱撑杂化炭膜，淀粉起到了造孔剂的作用，丰富了炭膜的孔隙结构，提高了炭膜的性价比。采用聚酰亚胺为前驱体制备的蒙脱土柱撑杂化炭膜，气体分离性能最为优异；考察了蒙脱土担载量、插层剂添加量、炭化温度、升温速率等条件对杂化炭膜孔道结构及气体分离性能的影响，所制备的杂化炭膜对H2, CO2, O2, N2显示了良好的分离性能，突破了传统炭膜的Robeson上界限，实现了孔道结构和分离性能的有效调控。本项目的研究成果丰富了杂化炭膜制备技术的基础理论，特别是在优化孔道结构和提高分离性能方面；对增强炭膜，降低成本，促进炭膜产业化应用方面也具有重要意义。