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.

水系统中离子的捕获和管理对社会具有广泛的重要性。最突出的应用之一是海水淡化，由于人口增长和气候变化对淡水资源造成压力，海水淡化正在成为一项日益重要的技术。近年来，电容去离子（CDI）作为一种潜在的低能耗替代更常见的海水淡化方法（例如反渗透）的方法受到越来越多的关注。 CDI 的工作原理是让盐溶液通过电化学电池，其中正盐离子和负盐离子固定在带相反电荷的多孔碳电极的表面上。与其他脱盐方法相比，CDI 的优点之一是，在初始离子捕获步骤之后，电极可以通过排放到单独的废水库中进行再生。在此步骤中，回收了一些用于离子捕获的能量，此外，电极的有效再生减少了结垢。尽管 CDI 前景广阔，但其效率在高盐浓度下会降低。在这方面，它并不与反渗透等其他处理海水的方法竞争。近年来，为了扩大 CDI 有效的浓度范围，人们进行了大量的研究工作。大多数开发都集中在材料和电池设计的优化上，并取得了相当大的成功，但令人惊讶的是，很少考虑离子行为或每个电极上发生的基本过程的细节。主要考虑因素之一是确保离子电荷由电极捕获的离子存储，而不是与进料电解质中的离子交换（这不会降低盐浓度）。该提案旨在加深对 CDI 的机理理解，并应用这些知识来控制离子存储机制，以优化除盐效率。这将通过使用详细的电化学分析和核磁共振 (NMR) 来完成，核磁共振 (NMR) 使我们能够“看到”并计算电极中捕获的离子，并将其与电化学响应和除盐效率相关联。我们将研究电极孔径和电解质特性（例如存在的离子的浓度和性质）如何影响它们的捕获方式。然后，该信息将用于通知和优化电池设计和操作条件（例如流速和电池电压）。我们提出的工作本质上必然是基础性的，其主要目标是提高对 CDI 基础科学的理解，而不是制造原型 CDI 堆栈。然而，通过与学术和工业合作伙伴的合作，我们的目标是使用并识别可扩展且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.