Production of Alkaline Plasma Activated Tap Water using Different Plasma Forming Gas at Sub-Atmospheric Pressure

Abstract

The present study demonstrates the successful production of alkaline plasma-activated tap water (PATW), addressing the challenge of acidity in traditional PATW for various applications. By carefully controlling the plasma-forming gases (oxygen, air, argon) and process parameters, such as PATW production at sub-atmospheric pressure, it is possible to shift the pH of acidic PATW towards the alkaline range, making it suitable for applications like agriculture, aquaculture, sterilization, wound healing, disinfection, and food preservation. The investigation involved the characterization of plasma and the identification of various plasma species/radicals. The impact of different plasma-forming gases on the pH of PATW and the concentration of reactive species in PATW was thoroughly analyzed. Plasma created using oxygen and argon led to the production of reducing or alkaline PATW, while air and air-argon mixtures resulted in an acidic or oxidizing nature. The study also discussed the stability of nitrate ions, nitrite ions, and hydrogen peroxide in PATW, shedding light on their behavior over varying plasma treatment times and plasma-forming gas. Finally, the investigation explored the effects of gas flow rates, gas pressures, water volume, and plasma discharge powers on the concentration of H2O2 in PATW, providing valuable insights into optimizing the production process.