2021 Fiscal Year Final Research Report

Creation of novel ion sieve electroactive permeable membranes for continuous separation and recovery technology of lithium

Research Project

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Project/Area Number	19K12395
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	Hirosaki University
Principal Investigator	Guan Guoqing 弘前大学, 地域戦略研究所, 教授 (90573618)
Co-Investigator(Kenkyū-buntansha)	吉田曉弘弘前大学, 地域戦略研究所, 准教授 (30514434) 阿布里提弘前大学, 理工学研究科, 教授 (70565374)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	電気活性膜 / リチウムイオン分離回収 / 電気化学的に制御できるイオン交換分離プロセス / 選択性透過膜 / 自己電気エネルギー回収 / 吸着容量 / 脱着 / 分離機構
Outline of Final Research Achievements	This study focuses on development of electractive materials with high selectivity and capacitance for the lithium ions in the coexistence of other metal ions. In particular, A scalable three-dimensional (3D) porous composite electroactive film consisting of λ-MnO2, reduced graphene oxide (rGO) and calcium alginate (Ca-alg) was successfully fabricated and employed for the selective extraction of Li+ ions with low concentration via an electrochemically switched ion exchange (ESIX) technology. As a result, the Li+ ion adsorption capacity of the obtained λ-MnO2/rGO/Ca-alg composite electroactive film reached up to as high as 32.7 mg g-1. In addition, an ESIX system for efficient and selective LiCl separation from brine lakes was developed based on a strategy of self-electrical-energy recuperation, in which the electric energy generated in the process of LiCl uptake was proposed to compensate the energy consumed for the desorption of ions as well as the regeneration of electrodes.
Free Research Field	化学工学
Academic Significance and Societal Importance of the Research Achievements	海水等溶液中の希薄なリチウムイオンの選択分離に対する新たな分離理論の構築、材料設計及びプロセス開発が必要である。本研究では、多イオン共存条件の下、高リチウムイオン選択性透過膜の創製を中心にし、新規電気活性イオン選択透過膜の合成方法を探索した。その同時に、Li-と伴う非金属イオン（特にBr-とCl-）を選択的に分離できる電気活性膜も合成し、Li-イオンと非金属イオン同時に選択的に分離できる省エネルギーの電気活性イオン選択分離システムを構築した。得られた研究成果は、Li+の分離回収に大きく貢献できるものと考えられる。また、Li+以外の様々な有価金属イオンの分離・濃縮を実現するための糸口ともなる。