石墨烯/聚酯多尺度非织造复合材料的构建及其对PM2.5多层次过滤机制

Nonwoven fabrics have been widely used in air filtration field due to its three-dimensional porous net-like structure. However, since the air pollution associated with atmospheric fine particulate matter (PM2.5, i.e., particles with an aerodynamic diameter of 2.5 micron or less) became more severe in China in recent years, people now put forward much higher requirements on nonwoven filters. In order to alleviate the contradiction between the filtering precision and filtration resistance of nonwoven fabrics, we take polyester (PET) needle-punched nonwoven fabrics as the research object, and introduce the graphene nanosheets with high specific surface area to fabricate a kind of multi-scale graphene/PET composite nonwoven fabric. The final composite nonwoven fabrics combined the porous net-like structure with high adsorption property, which could make the filtering precision and filtration resistance of nonwoven fabrics be simultaneously enhanced. Moreover, the multi-level filtration mechanisms of PM2.5 will be studied by testing the filtering precision and filtration resistance of graphene/PET multi-scale composite nonwoven fabrics and analyzing the changes of structure for both graphene nanosheets and PET needle-punched nonwoven fabrics. This project will provide the theoretical and experimental foundation of fabricating the multi-scale nonwoven filters, and significantly broaden the application of graphene nanosheets in air filtration fields.

非织造材料因其独特的三维网状多孔结构在空气过滤领域已得到广泛应用，但其对PM2.5的过滤效果却差强人意，存在过滤精度与透气量相互制约的问题。本项目以聚酯纤维针刺非织造材料为改性基体，借助等离子体处理、改进电泳沉积以及酰胺化反应技术，将具有超高比表面和吸附特性的石墨烯引入聚酯非织造材料的纤维表面，构建石墨烯/聚酯多尺度非织造复合材料，实现对PM2.5的多层次过滤。分析等离子体处理、改进电泳沉积以及酰胺化反应的条件参数对石墨烯含量、表面吸附特性以及石墨烯/纤维界面结构的影响，表征过滤后PM2.5在石墨烯及聚酯纤维表面的吸附量以及分布状态，研究非织造复合材料的结构、形貌与透气性、过滤效率、过滤阻力的构效关系，掌握多尺度非织造复合材料的结构调控方法，揭示其对PM2.5的过滤机制。项目将为多尺度非织造复合过滤材料的结构设计及应用提供理论依据和实验基础，对于推动我国雾霾空气治理技术的发展具有重要意义。

非织造材料因其独特的三维网状多孔结构在空气及液体过滤领域已得到广泛应用，但其过滤效果却仍存在不足，存在过滤精度与透气量相互制约的问题。为此本项目开展了以下研究：a）探索了不同结构形貌的空气过滤非织造材料的结构、形貌对功能性（透气性、过滤性）的影响规律，并分析其原因；b）采用后整理技术对空气过滤材料进行处理，分析了后整理对滤料的透气量和过滤效率的影响；c）在此研究基础上，本项目利用等离子体引发接枝技术,对聚丙烯非织造布进行表面处理与改性，使其接枝-COOH，-NH2等基团，然后再进行电泳沉积氧化石墨烯，构建了石墨烯/丙纶复合非织造材料，在一定程度上提升了过滤材料的透气和过滤性能。但实验结果不够理想，过滤精度仍低于预期；d）此外，本项目组还提出将具有高比表面积和高吸附特性的氧化碳纳米管组装到以聚丙烯非织造布为基底支撑层的静电纺聚丙烯腈纳米纤维膜表面，构建出一种多层次的微纳米级梯度结构丙纶/聚丙烯腈-碳纳米管纤维复合膜，该复合膜对靛蓝染料具有很高的截留率，同时兼具较高的水通量。复合膜对靛蓝染料的截留率为98.73%，水通量为3891.85 L/m2 •h。综合分析了上述结果，探讨了复合非织造材料的微观结构形貌对其空气和液体过滤性能的影响规律，掌握了多尺度非织造复合材料的结构调控方法。项目将为多尺度非织造复合过滤材料的结构设计及应用提供理论依据和实验基础，对于推动我国环境污染治理技术的发展具有重要意义。