Upscaling shock wave electrodialysis for scalable deionization

Shock wave electrodialysis (SWED) leverages microfluidic channels within surface-charged porous materials to induce ion concentration polarization (ICP) under over-limiting current conditions, enabling energy-efficient water reclamation and resource recovery. To date, only a limited number of studies have evaluated single-cell SWED prototypes using borosilicate glass frit (BSGF) operated at a small scale with an active membrane area of 200 mm² per cell and superficial flow velocities of 10 ^-5∼10^-6 m/s. Here, we report a bench-scale, multi-cell SWED module based on a cation-exchange membrane configuration, featuring an active membrane area of 4,000 mm² per cell and a superficial velocity of approximately 10^-4 m/s, representing a two-order-of-magnitude increase in throughput compared with previous studies. We further developed a cation-exchange resin wafer that serves as a promising alternative porous medium for electrodialysis-based systems operating under over-limiting current conditions, and systematically compared its performance with that of conventional BSGF. Experimental results demonstrate a remarkable deionization efficiency of over 90% during continuous operations around 60 min, with a remarkable current efficiency of 64 ± 12% (n = 4), depending on operating conditions and stack configurations. We further elucidate the mechanisms of ICP induced by over-limiting current under varying operational conditions. Finally, we propose design strategies to optimize SWED reactors, highlighting the trade-offs among separation efficiency, water recovery, and energy consumption. This study demonstrates for the first time that SWED energy efficiency can be significantly improved through geometric optimization, with thinner channels and multi-cell configurations preserving treatment capacity and deionization performance at lower energy consumption. This study marks an important milestone in advancing SWED toward practical scale-up, demonstrating its potential as an energy-efficient platform for large-scale water treatment and deionization.