With the rapid development of plasma technology, the agricultural sector has recently introduced a wide application of plasma activated water with the potential to increase the germination, growth and grain yield of crops.
Atmospheric pressure cold plasma in the gas phase contains active species such as charged particles (electrons and ions), ozone, atomic oxygen, superoxide radical, hydroxyl radical, nitrous oxide radical, and nitrous oxide radical. When these gaseous active species dissolve in the liquid, a dynamic chemical reaction takes place to form liquid active species. The resulting chemically active species, with short or long lifetime, can achieve the overall biological effect associated with plasma activated water.
It was previously confirmed that nitrate, nitrite and hydrogen peroxide (H2O2) as stable and long-lived active species are detected in plasma activated water. Therefore, quantitative detection of H2O2 is important for considering the biological effects of crops associated with plasma activated water.
The generation of various active species by plasma flow depends on various parameters such as plasma power type, carrier gas species, electrode structure, applied voltage, voltage polarity, processing time, gas flow rate, solution volume, distance between electrode and liquid surface, solution composition, pulse duration, etc.
The use of air as a plasma working gas has many advantages such as safety, low cost and convenience for operation of the device.
An Song Il, a researcher at the Nano Physics Institute, has conducted an experiment by choosing two types of discharge electrode structures in which air is in contact with water as a working gas, and compared the characteristics of the active species produced in water.
The result showed that the concentration of the total active species in the plasma activated water by mode 1 is higher than that of mode 2.
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