Collaborative Research: High-performance water purification membranes made of 2D zeolite nanosheets

合作提案项目负责人：米宝霞/刘冬霞提案编号：1706059/1705284随着世界水资源需求接近淡水供应，清洁水生产已成为一项全球性挑战。膜技术通过净化非传统水源（如海水、微咸水和废水）来提供淡水，有望解决这一问题。通常，聚合半透膜已被用于净化过程。聚合物膜在去除水中盐分方面是有效的，但它们存在膜污染、低氯耐受性和低水渗透性，导致投资和维护成本高。该项目的一个重点是通过使用一种新型的二维（2-D）沸石纳米材料开发下一代膜来克服这些问题。高性能沸石膜可能在其他领域有其他应用，如用水点处理、可再生能源生产和药物输送。教育活动特别针对K-12女学生、代表性不足的少数群体和普通大众。工程专业学生的多样性和公众对科学技术的兴趣都将得到加强。从这个项目中获得的知识可能有助于指导设计新的过程，以帮助解决全球水危机。主要研究人员计划利用二维沸石纳米片的独特性质，作为全新的材料来制造高性能的水净化膜。阻碍沸石膜实现其在水净化应用中的潜力的一个问题是难以在合成膜中实现高沸石负载；因此，在不牺牲膜的机械强度或结构完整性的情况下，开发高效的策略来大幅增加沸石负载将是研究的重点。pi采用了一种新颖的跨学科方法：(1)利用新兴的二维沸石纳米片，它具有更高的外表面积，更多的表面官能团和独特的柔性形状，与之前所有研究中使用的三维沸石纳米颗粒相比，所有这些都将大大增强膜的物理化学性质；(2)定制一种逐层技术，将二维沸石纳米片理想地组装成超薄沸石膜，具有极高的负载和显著提高的水净化性能；(3)深入研究了水/污染物传输的潜在机制，并评估了新型沸石膜的潜在原位再生和长期稳定性。与传统的聚酰胺或以前的沸石-聚合物纳米复合膜相比，沸石纳米片膜将具有许多显著的优点，包括：(1)更高的沸石负载，(2)更高的透水性，(3)通过原位再生改善污染控制，(4)提高化学稳定性。实验研究了沸石纳米片膜的结构和功能，以及沸石纳米片膜中水和溶质的传输。

Collaborative Proposal PI: Baoxia Mi/Dongxia LiuProposal Number: 1706059/1705284 Clean water production has become a global challenge as the world water demand is approaching the available fresh water supply. Membrane technology holds great promise for solving this problem by supplying fresh water through purification of nontraditional sources such as seawater, brackish water, and wastewater. Typically, polymeric semi-permeable membranes have been used in the purification process. Polymeric membranes are effective in removing salt from water, but they suffer from membrane fouling, low chlorine tolerance, and low water permeability, leading to high capital and maintenance costs. A focus of this project is to overcome these problems by developing a next-generation membrane using a novel 2-dimensional (2-D) zeolite nanomaterial. High-performance zeolite membranes may have other applications in other areas, such as point-of-use water treatment, renewable energy production, and drug delivery. The educational activities particularly target K-12 female students, underrepresented minority groups, and the general public. Both the diversity of students in engineering careers and the public interest in science and technology will be enhanced. The knowledge gained from this project may help guide the design of new processes to help resolve the global water crisis. The Principle Investigators plan to exploit the unique properties of 2-D zeolite nanosheets as radically new materials to make high-performance membranes for water purification. One problem impeding zeolite membranes from realizing their potential in water purification applications is the difficulty of achieving high zeolite loading in the synthesized membrane; therefore, developing highly efficient strategies to drastically increase zeolite loading without sacrificing membrane mechanical strength or structural integrity will be a research focus. The PIs take a novel interdisciplinary approach that: (1) exploits the emerging 2-D zeolite nanosheets that have a higher external surface area, more surface functional groups, and a unique flexible shape, all of which will lead to much enhanced physicochemical properties of membranes when compared with those generated by 3-D zeolite nanoparticles used in all previous studies; (2) customizes a layer-by-layer technique that will ideally assemble the 2-D zeolite nanosheets into an ultra-thin zeolite membrane with extremely high loading and significantly improved performance in water purification; and (3) performs a thorough investigation to elucidate the underlying mechanisms for the water/contaminant transport and to evaluate the potential in-situ regeneration and long-term stability of the novel zeolite membranes. Compared with traditional polyamide or previous zeolite-polymer nanocomposite membranes, the zeolite nanosheet membrane will offer many significant advantages including: (1) higher zeolite loading, (2) higher water permeability, (3) improved fouling control through in-situ regeneration, and (4) improved chemical stability. The PIs investigate the structure/function of the zeolite nanosheet membrane and the water and solute transport in these novel zeolite membranes.