Characteristics of discharged sea water generated by underwater plasma system

Plasma–Saline Water Interaction: A Systematic Review

“…Of the 37 articles chosen, most of the investigations do not apply to an isolated research field, but as associations between environmental and biological, physical or chemical studies, for example [ 20 , 21 , 22 , 23 , 29 , 38 , 50 , 52 ]. However, considering the main parameters investigated by the authors and the research objectives, a distribution of studies in macro-research fields allows a more detailed visualization of the main sectors in which the treatment is currently used ( Figure 2 ).…”

“…Acidification caused by plasma can occur with the injection of ions, which react with species in the saline water, such as salts and hydroxyl, forming H 3 O + [ 71 ]. The mechanism of this process is mainly attributed to two pathways: (i) the interaction between electrons, H 2 O, OH − , and N 2 , resulting in the formation of acids such as HNO 3 and HNO 2 [ 19 , 21 , 49 , 56 ]; and (ii) the ionization of water by energetic particles of the plasma, which lead to an increase in the concentration of H + in the solution, in a controlled atmosphere (absence of N 2 ) [ 25 ]. As acidification occurs initially on the surface and then is homogenized in the volume of the solution, these changes may be more relevant for a higher V/A P-L ratio [ 25 ].…”

“…The production of these species grows with the increase of the energy of the species interacting with the surface of the solution, effective area of interaction, and treatment time. In saline water, the chlorine radical can reduce the concentration of NO 2 − and increase the pH of the reaction medium due to the occurrence of Equation (2) [ 21 , 39 , 48 , 51 ] as follows: HClO + NO 2 − → ClNO 2 + OH − …”

“… Macro-research fields of the included studies in this review. Fundamental [ 21 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 50 , 52 , 54 , 58 , 59 ], plasma medicine [ 20 , 22 , 31 , 32 , 38 , 39 , 40 , 48 , 49 , 51 , 55 , 56 , 60 ], engineering [ 24 , 25 , 26 , 53 ], and environmental [ 19 , 23 , 27 , 28 , 29 , 30 , 57 ]. …”

“…When plasma touches the surface of saline water, the reactive species interact with the solvated charges in the saline water and induce additional physicochemical transformations, having as one of the consequences the accelerated and selective crystallization of salts, for example, which opens up possibilities for use in desalination processes, chemical extraction, and others [ 19 ]. To date, the effects of the interaction of plasma with saline water have been reported for sterilization and disinfection [ 20 , 21 , 22 , 23 ]; desalination, precipitation, and crystallization of salts [ 19 , 24 , 25 , 26 ]; catalysis of oxidative processes [ 27 , 28 , 29 ]; decontamination of organic pollutants [ 30 ]; alternative sources of nitrites/nitrates [ 31 , 32 ]; etc. There are different applications and different types of plasma sources, which differ strongly from each other, making it difficult to summarize or even compare the results of different types of sources from a chemical and physical point of view.…”