Shear-Enhanced Ion Rejection during Seawater Freezing

YX Wang and DC Shi and GZ Liu and BL Huang and ZG Li, JOURNAL OF PHYSICAL CHEMISTRY B, 127, 10404-10410 (2023).

DOI: 10.1021/acs.jpcb.3c05432

Ion rejection during seawater freezing is the basis for freeze desalination. A high ion rejection rate is desired for improving the performance of freeze desalination. In this work, we propose a method to enhance the ion rejection rate through external shear, which is demonstrated through molecular dynamics (MD) simulations and experiments. MD simulations show that the ion rejection rate increases with an increasing shear rate. This is attributed to the disruption of the hydration bonds between ions and water molecules in the hydration shell caused by the shear. Consequently, the mobility of ions is increased, and the energy barrier is reduced at the ice-water interface such that ions have a greater chance of diffusing into the aqueous solution, leading to an enhanced ion rejection rate. The MD results in this work are qualitatively confirmed by experiments and provide insights into the enhancement of the ion rejection rate through external parameters.

Return to Publications page