“一锅法”构建金属纳米粒子/功能化石墨烯原位掺杂混合基质膜及其膜结构与渗透汽化性能调控

Membrane separation technology play an important role in the development of ecological and environmental-friendly society. In this project, the mixed matrix membranes with metal-nanoparticle/graphene composite are designed via a one-pot method. Metal-nanoparticle/graphene composites with three-dimensional structure are formed by reverse micelle microemulsion, and the mixed matrix membranes are prepared by in-situ microemulsion polymerization route. Metal-nanoparticle/graphene composites can both increase the free volume of the mixed matrix membranes, and possess the facilitated transport function for pervaporation of organic mixtures, which enhance the permeability and permeation selectivity of the membranes, thus break through “trade-off” effect of general polymer membranes. The project study the composition of reverse micelle microemulsion, the precursors of metal-nanoparticle, structure of functionalized graphene on influence of the microstructure and performance of the mixed matrix membranes, reveal the regulatory rules of the microstructure and performance of the mixed matrix membranes, elucidate the facilitated transport characteristics of the mixed matrix membranes, develop a novel mixed matrix membrane with excellent property and the preparation method of the membranes, enhance the level of application of membrane separation technology. It is an innovative work, and which has important academic value and practical significance.

膜分离技术在当前我国建设生态、环境友好型社会中发挥重要作用。本项目拟通过反胶束微乳液及其聚合“一锅法”构建金属纳米粒子、功能化石墨烯二元原位掺杂、协同作用的混合基质膜。首先利用反胶束微乳液在功能化石墨烯片层上原位生长、沉积金属纳米粒子，得到三维结构的金属纳米粒子/功能化石墨烯复合物，再通过微乳液聚合制备混合基质膜。通过金属纳米粒子、功能化石墨烯二元原位掺杂、协同作用增加混合基质膜的自由体积，并赋予混合基质膜促进传递功能，突破常规聚合物膜的trade-off效应。项目研究反胶束微乳液组成、金属纳米粒子前驱体、功能化石墨烯结构等对混合基质膜结构与渗透汽化性能的影响，阐明利用反胶束微乳液调控混合基质膜结构与性能的机制和规律，开发性能优异的混合基质膜及其设计与构建方法，提升膜分离技术应用水平。这是一项基于二元、低维纳米材料原位掺杂、协同作用构建混合基质膜的创新性工作，具有重要的学术价值和实际意义。

渗透汽化技术以其高效、节能和环保等特点，被广泛运用于分离各种有机物，倍受学术和工业界的高度重视。项目采用三种聚氧乙烯-聚氧丙烯-聚氧乙烯醚表面活性剂(L31、L35、L61)构建的反相微乳液制备纳米银粒子(AgNPs)(其中L31与L61的亲水亲油平衡值(HLB)值较为接近但分子量差异较大，L35与L61分子量较为接近但HLB值差异较大)，再通过原位聚合法制备纳米银(AgNPs)和氧化石墨烯(GO)二元共掺杂的混合基质膜，用于渗透汽化分离苯与环己烷。首先研究反相微乳液体系的组成及结构，特别是反相微乳液体系中表面活性剂的结构性质(分子量、HLB值) 及添加量(mL)、AgNO3水溶液浓度(CAgNO3)、增溶水量(ω，即水与表面活性剂的摩尔数之比)对体系稳定性的影响，获得了L31、L35、L61构建的反相微乳液体系AgNPs/(MMA+St)/L31、AgNPs/(MMA+St)/L35、AgNPs/(MMA+St)/L61的宜适的组成范围。向多种含有纳米Ag粒子的反相微乳液体系中添加适量的氧化石墨烯(GO)、引发剂进行微乳液聚合反应，通过反应时间调控聚合乳液的粘度。继续采用反相微乳液及其聚合，结合涂覆法分别制备了AgNPs/GO/Poly(MMA-St)(L35)及AgNPs/GO/Poly(MMA-St)(L61)混合基质膜，并进行溶胀吸附及渗透汽化实验考察膜的扩散及分离性能。发现，加入了Ag纳米粒子的混合基质膜分离因子为9.4，渗透通量达到了940.36 g·m-2·h-1，分别为Poly(MMA-St)膜分离因子的8.5倍，渗透通量的3.2倍，说明Ag引入能有效提高膜对苯与环己烷混合体系的渗透汽化分离性能，进一步添加0.3wt%的GO后，AgNPs/GO/Poly(MMA-St)(L31)膜的分离因子为11.9，渗透通量达到了1265.49 g·m-2·h-1，分别为Poly(MMA-St)膜分离因子的10.8倍，渗透通量4.3倍，表明GO的引入能进一步提高膜对苯与环己烷混合体系的渗透汽化分离性能。