Experimental study on seawater freeze desalination based on ultrasonic vibration

Seawater freeze desalination is a promising technology with low energy consumption; however, the presence of salt inclusions during the freezing process presents a challenge to enhancing desalination efficiency. While ultrasonic vibration has been proven effective in reducing the supercooling degree and energy consumption in pure water freezing, its impact on seawater desalination efficiency remains to be investigated. This study experimentally explores the characteristics of seawater freeze desalination under ultrasonic vibration. An ultrasonic-assisted seawater freeze crystallizer was designed, and experiments were conducted to compare and analyze the freeze desalination performance of the crystallizer with and without ultrasonic vibration. The findings reveal that ultrasonic vibration significantly enhances desalination by promoting the formation of smaller ice crystals. Compared with ordinary freeze desalination, the desalination rate has increased significantly by 18.18 % -67.86 %, and more significant effects were observed at higher salinity levels. Additionally, the application of ultrasonic vibration accelerates the icing process by approximately 8 %. Notably, during continuous desalination operations, the effectiveness of ultrasonic vibration gradually diminishes as salinity decreases. Nonetheless, the ultrasonic vibration-based freeze-reverse osmosis (Ultrasonic-Freeze-RO) method offers significant advantages in terms of reduced costs and energy consumption compared to both freeze-reverse osmosis (Freeze-RO) and traditional reverse osmosis (RO) methods.