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

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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.