Simultaneous generation of acidic and alkaline water using atmospheric air plasma formed in water

Abstract

Plasmas on water surfaces and in water can be generated at atmosphere pressure using several kinds of gases, including helium, argon, oxygen, and air. Nitrates are generated in water through the interaction between water and atmospheric plasma that uses ambient air. Water that has been made acidic by the generation of nitric acid and the acidic water can be used for the sterilization of medical instruments, toilet bowls, and washing machines. Dishwashers are another potential application, as alkaline water is needed to remove grease from tableware. To investigate the production of alkaline water and its mechanism, gas component analysis was performed using an atmospheric quadrupole mass spectrometer. It was found that hydrogen gas evolves from the water surrounding both the positive and negative electrodes. The gas and water analyses carried out in this study revealed that acidic water of pH 2.5 and alkaline water of pH 10 can be simultaneously generated by our ambient air plasma device, which has been altered from our original model. The alterative plasma device has a partition wall, which is made of conductive resin, between the positive and negative electrodes.