Effect of Cold Atmospheric Plasma on Hypersaline Water Precipitation

Seawater waste from salt production or desalination plants contains high concentrations of dissolved salts, which negatively impact the environment. In the present work, the cold atmospheric plasma (CAP) technique was used in the treatment of this residue, aiming to investigate its potential in the extraction and separation of salts. A module pulsed voltage equal to 11.5 kV generated dielectric barrier discharges (DBDs) between a falling drop inside a glass tube and a copper ring outside it. The treated drops were filtered and the precipitated salts collected and analyzed. The total mass, morphology, chemical composition, and crystalline phase of the precipitates were determined. The results were compared with the precipitation of hypersaline droplets without plasma treatment. It was found that, in addition to superior precipitation rate, the droplets of plasma-activated hypersaline water produced smaller crystals and chemical compositions different from those precipitated by evaporation. These results are encouraging for the use of this technique in the recovery of these residues, both from the salt industry and from the seawater desalination plant.