Fundamental and Practical Studies of Capacitive Deionization Using Asymmetric Nanoporous Oxide Electrodes

0852780 Anderson电容去离子(CDI)是一种通过隔离带电表面附近的双电层中的离子来操作的过程。基本上，离子的溶液流经一对高度多孔的导电电极，阴离子或其他带负电荷的物种在正极被除去，而阳离子或带正电的物种在负极从溶液中分离出来。在移除过程中，能量以电容的方式存储，并随时可用来降低能源消耗成本。在充电循环中，施加反向偏压，迫使电化学隔离的离子以盐水的形式释放，就像在反渗透和蒸发蒸馏过程中一样。通常认为，CDI的盐水产量低于RO作业的盐水产量。这一建议包括对CDI过程的基础和实际研究，该过程使用一组新型的不对称电极，表面涂有纳米孔氧化物。这项研究将利用电化学阻抗测量和与真实世界的孔大小和孔大小分布相关的模型来解释我们的结果。此外，还将开发一种原位电化学FTIR系统来研究这些纳米孔氧化物电极中的分子行为。从实用的角度来看，许多CDI电极必须串联工作，电子控制，并与水的成分和流量相匹配，以实现最佳的离子去除。在拟议研究的这一部分，将把一堆电极组装成一个模块，并就离子去除与时间、电极表面积和每加仑处理水的能源成本进行基准比较。这部分工作将分四个部分完成：1.为我们的电极选择最佳的支撑材料2.用我们最好的纳米多孔氧化物薄膜覆盖这个支撑材料。3.在四对电堆中测试电极，最后4.建立CDI原型。潜在地，CDI可以作为一种海水淡化过程进行有利的竞争。提议的CDI系统可用于市政设施或第三世界社区，为迫切需要的人提供饮用水。该项目将培养一名博士和几名本科生。它将有助于更新实验室仪器，以便在研究和教学中使用。此外，这个项目将以一种改进的方式用作每年秋季学期在威斯康星大学教授的本科工程学入门课程的设备模板。在这门课上，16名学生将组成一个工程团队，与无国界工程师组织(EWB)合作开发一种太阳能CDI系统，EWB将在肯尼亚进行现场测试。

0852780AndersonCapacitive deionization (CDI) is a process that operates by sequestering ions in the electrical double layer near charged surfaces. Essentially, a solution of ions flows through a highly porous conducting pair of electrodes and anions or other negatively charged species are removed at the positive electrode while cations or positively charged species are separated from solution at the negative electrode. During the removal process, energy is being stored in a capacitive fashion and is readily available to lower the cost of energy consumption. In a recharge cycle, a reverse bias is applied forcing the electrochemically-sequestered ions to be released as brine, much as in both RO and evaporative distillation processes. Brine production is generally considered to be less for CDI than in RO operations. This proposal includes fundamental as well as practical studies of the CDI process using a novel asymmetric set of electrodes coated with nanoporous oxides. This research will utilize electrochemical impedance measurements and models tied to real-world pore size and pore size distributions to interpret our results. In addition, an insitu electrochemical FTIR system is to be developed to study molecular behavior inside these nanoporous oxide electrodes. From a practical perspective, many pairs of CDI electrodes must work in tandem, controlled electronically, and matched to water composition and flux for optimal ion removal. In this part of the proposed studies, a stack of electrodes will be assembled into a module and benchmarked with respect to ion removal versus time, electrode surface area, and energy cost per gallon of water processed. This portion of the proposed work will be completed in four parts: 1. Choosing an optimal supporting material for our electrodes 2. Coating this support with our best nanoporous oxide films. 3. Testing electrodes in four pair stacks and finally 4. Building a CDI prototype. Potentially, CDI can compete favorably as a desalination process. The CDI system proposed could be used by municipal facilities or in third-world communities providing potable water to people in severe need. This project will result in the training of one PhD and several undergraduate research students. It will contribute to renewed laboratory instrumentation to be employed in both research and teaching. In addition, this project will be used in a modified fashion as a device template for an undergraduate introductory course in engineering taught at the University of Wisconsin each fall semester. In this class, 16 students, forming an engineering team will cooperate with Engineers Without Borders (EWB), to develop a solar-powered CDI system that EWB will field-test in Kenya.