Separation of ionic species from multi-component aqueous electrolytes by nanoporous electrodes

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K12249
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64030:Environmental materials and recycle technology-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Kenji Kiyohara 国立研究開発法人産業技術総合研究所, 材料・化学領域, 主任研究員 (30344188)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 多孔質電極 / イオン種選択的吸着 / 分子シミュレーション / 脱塩

Outline of Final Research Achievements

To assess the possibility of separating ionic species from multi-component electrolytes by utilizing the characteristic thermodynamic behaviors of ions that are electrochemically adsorbed in porous electrodes, we made theoretical analyses by using molecular simulation and experimental analyses by using electrochemical and ion-concentration measurements. The theoretical analyses showed that the potential barrier that an ion needs to overcome in the process of being adsorbed in the porous electrodes strongly depends on the ion species, pore size of the electrode, and applied voltage. Specifically, it was shown that mono-valent and multi-valent ions could be separated by this method. The experimental analyses showed results consistent with the theoretical analyses, including that the potential barriers for a porous electrode with pores of sizes comparable to the ion size strongly depend on the applied voltage.

Free Research Field

分子シミュレーション

Academic Significance and Societal Importance of the Research Achievements

現在、海水、鉱山水、工業排水を含むさまざまな「水」や電子廃棄物の溶出液などから特定のイオン種を選択的に回収する方法としては沈殿法などが用いられているが、使用する薬品や生成する二次的な廃棄物の量をより削減できる手法が求められている。本研究で検討している多孔質電極によるイオン種選択的吸着の手法は、省エネルギーで薬品を使わず、また廃棄物の減容も期待できることから、さまざまな多成分電解質から有害イオンの除去や有価イオンの再利用を行うための新しい技術になる可能性がある。