Electrodialysis for metal removal and recovery: A review

Electrodialysis (ED) is a multipurpose technology that can be used for treating acidic effluents containing metal species. Its continuous operation capacity, scalability, and easy operation can solve most of the drawbacks of current technologies, and the direct reuse of concentrated metal streams can avoid the need for chemical addition and precipitation. Hence, ED emerges as a promising technology with a huge growth potential to concentrate, separate, and selectively recover metals from acidic effluents. This critical review aims to (I) review and discuss the types of ED processes and their state-of-the-art, (II) provide an insight on the most important parameters behind the ED technology, and (III) evaluate the limitations, perspectives, and future research trends in this field. Typical problems including precipitation in the setup, waste management, and scale-up of the system are discussed and solutions are suggested. In addition, insights on materials development on both membrane and electrode are provided for further advancing the ED technology in metal recovery. We hope the review can shed light on the ED development for metal resources recovery from industrial and municipal wastewaters moving one step further towards circular water treatments.