Investigating Non-Thermal Plasma-Induced Precipitation in Hypersaline Waters

Abstract

In the present study, non-thermal plasma (NTP) of dielectric barrier discharge (DBD) was used to investigate the precipitation of salt from hypersaline waters obtained by evaporating seawater. A dripper was used to release drops of water over the NTP discharge between the droplet surface and a copper ring in a glass tub working as a DBD. Results showed that the precipitation rate of the NTPtreated solution was significantly higher than that of the untreated solution, with a larger number of small crystals formed, and multiple charged ions preferentially precipitated. These findings suggest that the external electric field from NTP aligns and weakens the hydration of ions, leading to the binding of dehydrated cations and anions, and inducing nucleation/precipitation. Additionally, the NTP discharge channels formed at the gas-liquid interface cause rapid dehydration of ions, which further induce nucleation and crystal formation. This could explain the preferential precipitation of small crystals containing multiple charged ions. Overall, the results demonstrate that NTP-DBD is a promising approach for efficient precipitation of salts from hypersaline waters.