Analysis of transport properties of radiation-grafted cation and anion exchange membranes and their application to reverse electrodialysis

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K06839
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Properties in chemical engineering process/Transfer operation/Unit operation
• Research Institution: National Institutes for Quantum and Radiological Science and Technology
• Principal Investigator: Sawada Shin-ichi 国立研究開発法人量子科学技術研究開発機構, 高崎量子応用研究所 先端機能材料研究部, 主幹研究員(定常) (70414571)
• Co-Investigator(Kenkyū-buntansha): 前川 康成 国立研究開発法人量子科学技術研究開発機構, 高崎量子応用研究所, 副所長(定常) (30354939)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 逆電気透析発電 / 放射線グラフト法 / カチオン交換膜 / アニオン交換膜 / 膜抵抗

Outline of Final Research Achievements

I developed the cation exchange membranes (CEMs) and anion exchange membranes (AEMs) by a radiation grafting method and then applied them for reverse electrodialysis (RED). CEMs were prepared by grafting of styrene into ethylene-co-tetrafluoroethylene (ETFE) base films and subsequent sulfonation. AEMs were prepared by grafting of chloromethylstyrene into ETFE films and subsequent quaternization. The resistance of the prepared CEMs and AEMs dramatically decreased with increasing the ion exchange capacity (IEC). The minimum resistance of the CEM and AEM was considerably lower than those of the commercial CEM and AEM. Five pairs of the grafted CEMs and AEMs were used for the RED. The high- and low-concentration sodium chloride solutions were supplied to the RED cell. The output power density was significantly higher than the cell employing the commercial CEMs and AEMs. It was demonstrated that the radiation-grafted CEMs and AEMs were suitable for RED application.

Free Research Field

膜分離工学、電気化学、放射線化学

Academic Significance and Societal Importance of the Research Achievements

逆電気透析発電は、海水と淡水から電気を生産する極めてクリーンな再生可能エネルギーである。これまで、RED発電の出力を上げるため、電気抵抗の低いカチオン交換膜(CEM)とアニオン交換膜(AEM)が模索されていた。本研究により、放射線グラフト重合法で作製した低抵抗のCEMとAEMを用いると、従来市販膜の場合と比べ、発電出力を大幅に向上できることがわかった。RED発電の産業実用化、ひいては再生可能エネルギーの普及に貢献し得る成果として、社会的な意義は大きい。