Mechanistic Understanding of Capacitive Deionisation (MU-CDI)

电容去离子的机理理解 (MU-CDI)

• 批准号: EP/V05001X/1
• 负责人: John Griffin
• 金额: $ 50.27万
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FV05001X%2F1
• 关键词: Mechanistic; Understanding; Capacitive; Deionisation; MU

The capture and management of ions in water systems are of widespread importance to society. One of the most prominent applications is water desalination, which is becoming an increasingly important technology due to population growth and climate change putting pressure on freshwater resources. In recent years, capacitive de-ionisation (CDI) has gained increasing attention as a potentially low-energy alternative to more common desalination methods such as reverse osmosis. CDI works by passing a saline solution through an electrochemical cell where the positive and negative salt ions are immobilized on the surfaces of oppositely-charged porous carbon electrodes. One of the advantages of CDI over other desalination methods is that following the initial ion capture step, the electrode can be regenerated by discharging into a separate effluent stock. In this step, some of the energy used for the ion capture is recovered, and furthermore, the efficient regeneration of the electrode reduces fouling. Despite the promise of CDI, its efficiency reduces at high salt concentrations. In this respect, it does not compete with other methods such as reverse osmosis for treatment of seawater. In recent years there have been considerable research efforts to extend the concentration range in which CDI is effective. Most development has focused on optimisation of materials and cell designs with considerable success, yet, surprisingly little consideration has been given to details of the the ion behaviour or the elementary processes taking place at each electrode. One of the primary considerations is to ensure that ionic charge is stored by ions being captured by the electrode, rather than being exchanged with those in the feed electrolyte (which does not reduce the salt concentration). This proposal seeks to develop a mechanistic understanding of CDI and apply this knowledge to control the ion storage mechanism to optimize the salt removal efficiency. This will be done through the use of detailed electrochemical analysis and the use of nuclear magnetic resonance (NMR), which allows us to "see" and count ions that are captured in the electrode, and correlate this with the electrochemical response and salt removal efficiency. We will investigate how the electrode pore size and electrolyte properties, such as concentration and the nature of the ions present, affect how they are captured. This information will then be used to inform and optimise the cell design and operational conditions (e.g., flow rate and cell voltage). Our proposed work is necessarily fundamental in nature with the key aim of improving the understanding of the underlying science of CDI, rather than fabrication of prototype CDI stacks. However, through our collaborations with academic and industrial partners, we aim to work with, and identify, scalable and commercially-relevant electrode materials.

对水系统中离子的捕获和管理对社会至关重要。最突出的应用之一是水的脱盐，由于人口增长和气候变化对淡水资源施加压力，它正成为一项越来越重要的技术。近年来，作为一种潜在的低能替代品，诸如逆渗透的替代方法（例如反渗透方法），电容式去离世（CDI）已越来越多地引起人们的注意。 CDI通过将盐溶液通过电化学细胞的盐溶液来起作用，在该电化学细胞中，将阳性和负盐离子固定在相对充电的多孔碳电极的表面上。 CDI比其他淡化方法的优点之一是，在初始离子捕获步骤之后，可以通过排放到单独的废水库存中来再生电极。在此步骤中，回收了用于离子捕获的某些能量，此外，电极的有效再生减少了结垢。尽管有CDI的承诺，但其效率仍以高盐浓度降低。在这方面，它不与其他方法（例如用于治疗海水的反渗透）竞争。近年来，已经进行了大量的研究工作，以扩大CDI有效的浓度范围。大多数开发都集中在优化材料和细胞设计方面，并取得了很大的成功，但令人惊讶的是，对离子行为或每个电极处发生的基本过程的细节几乎没有考虑。主要考虑因素之一是确保通过电极捕获离子来存储离子电荷，而不是与进料电解质中的离子电荷（不会降低盐浓度）交换。该提案旨在对CDI建立机械理解，并应用此知识来控制离子存储机制以优化盐去除效率。这将通过使用详细的电化学分析和核磁共振（NMR）的使用来完成，这使我们能够“看到”和电极中捕获的计数离子，并将其与电化学响应和去除盐效率相关联。我们将研究电极孔的大小和电解质特性，例如浓度和存在的离子性质如何影响它们的捕获方式。然后，该信息将用于告知和优化单元格设计和操作条件（例如流速和电池电压）。我们提出的工作在本质上必然是基本的，其关键目的是提高对CDI的基本科学的理解，而不是制造原型CDI堆栈。但是，通过与学术和工业合作伙伴的合作，我们的目标是与电极材料合作并确定与可扩展和商业相关的电极材料。

项目成果

Understanding the Chemical Shifts of Aqueous Electrolyte Species Adsorbed in Carbon Nanopores.

了解碳纳米孔中吸附的水电解质物质的化学位移。

• DOI: 10.1021/acs.jpclett.2c02260
• 发表时间: 2022
• 期刊: The journal of physical chemistry letters
• 作者: Sasikumar A

Capacitive de-ionisation: An electrochemical perspective

• DOI: 10.1016/j.coelec.2022.101084
• 发表时间: 2022-07-14
• 期刊: CURRENT OPINION IN ELECTROCHEMISTRY
• 影响因子: 8.5
• 作者: Dryfe, Robert A. W.;Griffin, John M.
• 通讯作者: Griffin, John M.