具有限域效应的碳基杂化层叠纳滤膜传质微结构的构筑与调控

At present, the research and development of efficient water treatment technology is the key to solve the problem of water shortage. Nanofiltration, as a membrane filtration technology between ultrafiltration and reverse osmosis, can achieve the goal of separating economically and efficiently in some other traditional separation technologies which are more difficult to meet. Nanofiltration membrane is mainly concerned with the confined mass transfer process. Until now, the mechanism of the confined mass transfer of such membranes is not yet clear and the preparation of related membrane materials is still at the stage of experience and exploration. In this project, we adopt the method of vacuum suction filtration to prepare graphene- oxide hybrid laminated membrane, to research: ①based on graphene-oxide with high quality, through the introduction of crosslinking agent (small molecules or nanoparticles) to optimize the preparation of the graphene-oxide hybrid nanofiltration membrane which layer spacing can be adjusted accurately (the layer spacing is less than 10nm), combined with the pore space and pore wall building properties of variable construction to produce the confined mass transfer porous structure; ②molecular simulation and experimental methods are combined to establish the quantitative relationship between the performance confined geometric domain structure size and surface properties of membrane, to reveal the confined mass transfer mechanism under the action of fluid mixtures, ion selective membrane permeability and breakthrough trade-off effecting. To provide the theory development and technical support for the water treatment technology of membrane.

目前，研究开发高效的水处理技术是解决水资源短缺问题的关键。纳滤作为一种介于超滤和反渗透之间的膜过滤技术，能够在一些其他传统分离技术较难满足的领域实现经济高效的分离目标。纳滤微孔膜主要涉及限域传质过程，目前对这类膜的限域传质机制认识尚不清晰，相关膜材料的制备尚处于经验摸索阶段。本课题以氧化石墨烯膜为研究对象，采取真空抽吸过滤的方法制备氧化石墨烯杂化层叠纳滤膜，主要研究：①以高质量的氧化石墨烯为基础，通过引入交联剂（小分子或者纳米粒子）优化制备层间距精确可调的氧化石墨烯杂化层叠纳滤膜（层间距小于10nm），结合孔道空间的构筑和孔壁性质的调变构建能产生限域传质效应的多孔结构；②将分子模拟计算与实验手段进行有效结合，通过建立限域结构几何尺寸、表面性质与膜性能的定量关系，揭示界面作用下流体混合物的限域传质机制，突破膜过程中离子选择性和渗透性的博弈效应。为拓展膜法水处理技术提供理论依据和技术支撑。

纳滤作为一种介于超滤和反渗透之间的膜过滤技术，近年来在饮用水软化、污水深度处理与回用、工业过程浓缩分离等方面得到了较为广泛的应用。本课题以GO膜为研究对象，通过引入小分子或者纳米粒子制备层间距可调的GO杂化层叠纳滤膜，创新性地构建具有限域传质效应的膜结构（层间距小于10nm）。最重要的是构建的具有限域传质效应的GO分离膜于其壁面具有无摩擦效应，导致传质阻力小，因此，其传质通量和选择性都高，有望成功突破渗透性和选择性的trade-off效应。课题的主要研究结果如下：.①通过尝试二氧化硅、不同尺寸纳米银、纳米金颗粒、聚丙烯酰胺、乙二醇和乙二胺、ZIF-8纳米颗粒等多种不同交联剂精确调控膜层间距，构筑传质通道的限域结构，成功制备了物理筛分和静电相互作用协同作用的杂化纳滤膜，并通过实验探究了其高通量与高截留性能的传输机制。.②在肾小球过滤功能的启发下，通过将层间距大、带正电荷的GO-PEI纳米片构建到层间距小、带负电荷的GO纳米片中，开发了一种尺寸和电荷双效应协同作用、具有可调控和可逆门控性能的氧化石墨烯杂化纳滤膜，并研究了其pH响应纳米通道的传输机理。.③通过复合二维解拉链碳纳米管uCNT，开发了一种位阻效应和电荷效应双协调作用的，具有显著水渗透性和精确筛分选择性的高性能GO基复合纳滤膜，并研究了其pH稳定性以及通过离散傅里叶变换（DFT）计算，研究了其染料截留机理。.本项目针对新型氧化石墨烯杂化纳滤膜的开发和水处理问题，开展具有限域结构（层间距小于10nm）的氧化石墨烯杂化膜的优化制备和限域结构对离子传输行为的影响规律和传质机理探讨。课题为深入理解氧化石墨烯膜过滤除污染过程提供理论基础，力争开发出能成功突破渗透性和选择性trade-off效应的、具有限域结构的新一代水处理膜材料。