New ES&T paper on the energy efficiency of electro-driven brackish water desalination

A new Open Access paper was published in the prestigious journal ES&T, from the group of prof. Meny Elimelech (Yale, USA) which discusses a detailed comparison between electrodialysis (ED) and membrane capacitive deionization (MCDI).

Patel et al. "Energy Efficiency of Electro-Driven Brackish Water Desalination: Electrodialysis Significantly Outperforms Membrane Capacitive Deionization", ES&T (2020).

According to the authors, "we provide the first systematic and rigorous comparison of the energetic performance of electrodialysis (ED) and membrane capacitive deionization (MCDI) over a broad range of brackish water desalination conditions."

The authors find that:

  • The energy consumption of ED is substantially lower than MCDI for all investigated conditions, with the energy efficiency being nearly an order of magnitude higher for many separations.
  • Even with idealized operation (complete energy recovery and reduction in energetic losses), the energy efficiency of MCDI remains lower than ED.

Finally, the authors emphasize that "for low feedwater salinities (< ~2 g/L), energy efficiency should be a secondary consideration in the choice of desalination technology, with capital cost, ease and reliability of operation, and additionally required treatment steps taking higher priority."