以銅鈷氧化物/功能化奈米碳管提升氧化還原介導電透析性能於海水淡化之應用

Abstract

海水蘊含豐富的淡水潛力，促使各類海水淡化技術迅速發展。儘管反滲透（RO）、多級閃蒸（MSF）與電滲析（ED）等傳統技術已被廣泛應用，近年來亦興起諸如電容式去離子法（CDI）、膜電容式去離子法（MCDI）以及流動電極電容去離子法（FCDI）等創新電化學技術。融合ED與CDI原理的氧化還原中介電滲析（Redox-ED）被視為一種具高能效潛力的新興淡化技術，然而Redox-ED 在實際海水環境中的效能仍受限制。本研究旨在透過引入CuO/Co₃O₄功能化碳奈米管（CNT），以提升Redox-ED系統的整體性能，進而增強淡化效率並降低能耗。研究首先以酸氧化法對CNT進行官能化處理，隨後經由水熱法合成CuO/Co₃O₄。SEM、EDS、XRD與XPS的結果證實該複合材料成功形成，而循環伏安（CV）與電化學阻抗（EIS）測試亦顯示其具優異的電化學特性（ΔEp = 0.26 V，Rct = 2.96 Ω）。改良後的Redox-ED系統展現出優異的脫鹽性能，其平均鹽去除速率（ASRR）達404.76 μg/min·cm²，電荷效率高於99%，且能量消耗低（摩爾能耗 Em = 61.24 kJ/mol，體積能耗 Ev = 1.44 kWh/m³）。在模擬海水（導電度43.21 mS/cm）條件下測試時，系統仍可達成333.70 μg/min·cm²的ASRR、91.74%的電荷效率、穩定的五循環操作表現，同時有效去除超過99.9%的二價陽離子。研究結果證實CuO/Co₃O₄-FCNT為推動Redox-ED邁向具規模性與永續性的海水淡化應用之有效添加材料。

Seawater holds immense potential as a freshwater source, prompting the development of various desalination technologies. While conventional methods such as reverse osmosis (RO), multistage flash (MSF), and electrodialysis (ED) are widely used, innovative electrochemical methods like capacitive deionization (CDI), membrane CDI (MCDI), and flow-electrode CDI (FCDI) have emerged. Combining ED and CDI principles, redox-mediated electrodialysis (Redox-ED) is a promising new technology for energy-efficient desalination. However, Redox-ED performance remains limited especially for real seawater conditions. This study aims to enhance Redox-ED performance by incorporating CuO/Co₃O₄-functionalized carbon nanotubes, thereby increasing desalination efficiency and reducing energy consumption. CNT were first functionalized via acid oxidation, followed by CuO/Co₃O₄ synthesis through hydrothermal treatment. SEM, EDS, XRD, and XPS confirmed successful material formation, while CV and EIS showed improved electrochemical properties (ΔEp = 0.26 V, Rct = 2.96 Ω). The modified Redox-ED system achieved high salt removal rates with ASRR (404.76 µg/min·cm²), high charge efficiency (>99%), and low energy consumptions (Em = 61.24 kJ/mol, Ev = 1.44 kWh/m³). In practical tests using synthetic seawater (43.21 mS/cm), Redox-ED with CuO/Co₃O₄-FCNT achieved 333.70 µg/min·cm² ASRR, 91.74% charge efficiency, stable operation over five cycles, and above 99.9% removal of divalent cations. These findings confirm CuO/Co₃O₄-FCNT as an effective additive for advancing Redox-ED toward scalable and sustainable seawater desalination.