Plasma–liquid interaction research has developed substantially in recent years due, mostly, to the numerous applications of cold atmospheric plasma (CAP). Plasma–liquid interactions are influenced by the concentrations of the ionic species present in the liquid environment, and few studies have paid attention to saline water, which generally mediates the reactions in many plasma applications. Therefore, the present review aims to explore the main results and the influence of variables on the modification of properties of saline water by CAP sources following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The searches were carried out in the Scopus, Science Direct, and Web of Science databases, resulting in the inclusion of 37 studies. The main effects of the interaction between CAP and saline water are (i) the production of reactive oxygen and nitrogen species (RONS); (ii) the increase in conductivity and decrease in pH, directly proportional to the increase in discharge voltage; (iii) and the effective area of interaction and the shortest distance between electrode and solution. Other effects are the localized evaporation and crystallization of salts, which make the interaction between plasma and saline water a promising field in the development of technologies for desalination and improvement of liquid properties.

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.