Electrochemical cleaning in membrane distillation: Mechanisms and operation strategies

초록

Membrane distillation (MD) effectively treats highly concentrated solutions due to its unique rejection mechanism, making it suitable for applications such as zero liquid discharge. However, inorganic scaling significantly limits its practical operation under high-recovery conditions. Electrochemical cleaning (EC) utilizing electrically conductive membranes emerges as an innovative strategy, overcoming limitations associated with conventional hydraulic flushing and chemical cleaning methods. In this study, the effectiveness and mechanisms of EC using direct current (DC) and alternating current (AC) operations were systematically investigated. AC-driven electrochemical cleaning outperforms DC, as it maintains flux recovery above 95 % at 1.0 V, whereas DC drops to 87.88 %. After three cycles, the flux-decline rate is lower with AC and energy consumption is reduced. Unlike DC, whose efficiency fades as the membrane recharges and crystals nucleate, AC's electrokinetic vibration and ionic convection prevent scale adhesion and enhance flushing. Thus, EC-AC offers a robust, energy-efficient pathway to sustain high-performance MD under severe scaling conditions.

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