Enabling Minimal Brine Discharge Desalination Using Intercalation Reactions

淡水枯竭在全球范围内威胁着人类的生计和安全。海水淡化，或从海水和咸水中去除盐离子，可能会增加淡水的获取，但联合生产盐水或废水需要昂贵的处理，而且在环境上不可持续。该项目的目标是开发一种具有成本效益、能源效率的盐水浓缩工艺，相对于联合生产的废盐水，将产生更多的淡水，使市政、农业和工业部门的大型海水淡化设施受益。与需要蒸发水的盐水处理的热过程不同，这项研究将研究一种新的过程，使用电力驱动的反应来以低能源和低成本浓缩盐水，同时淡化给水。这些离子进入材料的反应被称为插层反应，过去曾被用来储存能量。然而，在卤水浓缩中使用它们需要更快、可逆地嵌入不同大小的各种离子，并且能量消耗较低。因此，该项目的主要目标是利用阳离子插层反应来表征、设计和模拟用于浓缩盐水的电去离子装置。海水淡化性能的预期改善将通过两种插层材料的协同效应实现，一种设计为接受较大的离子，另一种设计为接受较小的离子。除了其直接的更广泛的影响和研究生的参与，这项研究还将通过编写和传播补充教育材料，扩大妇女和代表性不足群体在STEM中的参与。将与伊利诺伊大学香槟分校(UIUC)外联协调员合作开发相关课程，创建一个面向设计的“3D-海水淡化”(用于海水淡化的数字设备设计)活动，将化学、工程和海水淡化联系起来。大学前妇女将通过游戏(数学、工程和科学中的女孩探险)营和UIUC的暑期教师讲习班参加这些STEM活动。该项目旨在开发用于海水淡化的改进的插层材料。这些改进的材料将固体插层纳米颗粒引入到多孔电极中，并显示出高体积负载量和便捷的电荷传输。通过组合不同组成的插层材料来协同浓缩溶解的碱/碱土盐混合物，可以通过组合具有小间隙的高容量材料和具有大间隙的低容量材料来平衡原生阳离子的吸收和吸收速率的假设将得到检验。许多插层材料的低电子传导性使得它们有必要与导电添加剂集成以维持高倍率循环。本文提出了一种新型的湿相转化工艺，通过促进电子渗流来制备具有高嵌入材料负载量和快速电子/离子传输的多孔电极。以前的模型和低盐度进料的电化学脱盐实验表明，流过电极和阴离子选择性膜可以提高盐分的去除。因此，电化学流量电池的分离性能将在不同的流场和分离器下进行实验表征。通过测量电极的有效传输特性，将验证计算模型，并将其用于量化单个器件组件中的局部能量损失机制。该项目的成果将是进一步了解混合插层材料的使用以及不同容量和间隙大小的材料之间的协同作用。该项目由化学、生物工程、环境和运输系统部门的分子分离和电化学系统计划联合支持。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Freshwater depletion threatens human livelihood and security globally. Desalination, or removing salt ions from sea and brackish waters, could increase freshwater access, but co-produced brine, or waste salt water, requires disposal that is costly and environmentally unsustainable. The goal of this project is to develop a cost-effective, energy-efficient brine concentration process that will produce more fresh water relative to the amount of co-produced waste brine, benefiting large-scale desalination facilities across municipal, agricultural, and industrial sectors. Unlike thermal processes for brine disposal, which require water evaporation, this research will investigate a novel process using electrically-driven reactions to concentrate brines with low energy and cost, while simultaneously desalinating feedwater. These reactions, in which ions move into a material, are called intercalation and have been used in the past for energy storage. However, their use in brine concentration requires faster, reversible intercalation of various ions with differing sizes, with low energy use. The primary objective of this project is, thus, to characterize, design, and model electric deionization devices using cation intercalation reactions for the concentration of brines. The expected improvement in desalination performance will be accomplished using the synergistic effects of two intercalation materials, one designed to accept larger ions while the second is designed to accept smaller ions. Beyond its immediate broader impacts and the involvement of graduate students therein, this research will broaden the participation of women and underrepresented groups in STEM through the development and dissemination of complementary educational materials. A design-oriented "3D-Desalination" (Digital Device Design for Desalination) activity linking chemistry, engineering, and desalination will be created with associated curricula developed in collaboration with University of Illinois Urbana-Champaign (UIUC) outreach coordinator. Participation of pre-college women in these STEM activities will occur through GAMES (Girls Adventures in Math, Engineering and Science) camps and through summer teacher workshops at UIUC.This project aims to develop improved intercalation materials for use in desalination. These improved materials incorporate solid intercalation nanoparticles into porous electrodes and exhibit high volumetric loading and facile charge transport. The hypothesis that raw cation absorption and absorption rate can be balanced by combining high-capacity materials having small interstitials with lower capacity materials having large interstitials will be tested by combining intercalation materials of differing composition to synergistically concentrate dissolved alkali/alkaline-earth salt mixtures. The low electronic conductivity of many intercalation materials necessitates their integration with conductive additives to sustain high-rate cycling. A novel wet-phase inversion process will be created here to fabricate porous electrodes with high intercalation-material loading and fast electron/ion transport by promoting electronic percolation. Previous modeling and experiments of electrochemical desalination with lower salinity feeds suggest that flow-through electrodes and anion-selective membranes increase salt removal. Separations performance of an electrochemical flow cell will, therefore, be characterized experimentally with various flow fields and separators. With measurements of the effective transport properties of electrodes computational modeling will be validated and used to quantify local energy loss mechanisms in individual device components. The outcome of the project will be further knowledge in the use mixed intercalation materials and the synergistic interaction between materials with differing capacity and interstitial size. The project is jointly supported by the Molecular Separations and the Electrochemical Systems programs in the Division of Chemical, Bioengineering, Environmental, and Transport Systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.