Enabling Minimal Brine Discharge Desalination Using Intercalation Reactions

淡水枯竭威胁着全球人类的生计和安全。海水淡化，或从海水和咸水沃茨中去除盐离子，可以增加淡水的获取，但共同产生的盐水，或废盐水，需要昂贵的和环境不可持续的处置。该项目的目标是开发一种具有成本效益，节能的盐水浓缩工艺，相对于共同产生的废盐水量，该工艺将产生更多的淡水，使市政，农业和工业部门的大型海水淡化设施受益。与需要水蒸发的盐水处理热工艺不同，本研究将研究一种使用电驱动反应的新工艺，以低能耗和低成本浓缩盐水，同时对给水进行脱盐。这些反应，其中离子移动到材料中，被称为嵌入，并已在过去用于能量存储。然而，它们在盐水浓缩中的使用需要具有不同尺寸的各种离子的更快、可逆的嵌入，并且使用低能量。本项目的主要目标是，因此，表征，设计和建模的电去离子装置使用阳离子嵌入反应的盐水浓度。脱盐性能的预期改善将使用两种嵌入材料的协同效应来实现，一种被设计为接受较大的离子，而第二种被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，这项研究将扩大妇女和代表性不足的群体在干通过开发和传播补充教育材料的参与。一个以设计为导向的“3D脱盐”（脱盐数字设备设计）活动将化学，工程和脱盐联系起来，并将与伊利诺伊大学香槟分校（UIUC）外展协调员合作开发相关课程。大学预科妇女将通过GAMES（女孩数学、工程和科学冒险）夏令营和UIUC的暑期教师讲习班参与这些STEM活动，该项目旨在开发用于海水淡化的改良嵌入材料。这些改进的材料将固体插层纳米颗粒结合到多孔电极中，并表现出高体积负载和容易的电荷传输。将通过组合不同组成的插层材料以协同浓缩溶解的碱金属/碱土金属盐混合物来测试通过组合具有小介电常数的高容量材料与具有大介电常数的较低容量材料可以平衡原阳离子吸收和吸收速率的假设。许多嵌入材料的低电子电导率需要它们与导电添加剂结合以维持高速率循环。一种新的湿相转化过程将在这里创建制造多孔电极具有高嵌入材料负载和快速的电子/离子传输，通过促进电子渗滤。以前的建模和实验的电化学脱盐与低盐度饲料表明，流通电极和阴离子选择性膜增加盐的去除。因此，电化学流动电池的分离性能将通过各种流场和分离器进行实验表征。通过测量电极的有效传输特性，将对计算建模进行验证，并用于量化单个器械组件中的局部能量损失机制。该项目的成果将进一步了解混合插层材料的使用以及具有不同容量和间隙尺寸的材料之间的协同作用。该项目由化学、生物工程、环境和运输系统部的分子分离和电化学系统项目共同支持。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.