Effects of plasma on physical properties of water: nanocrystalline-to-amorphous phase transition and improving produce washing

TL;DR

This paper investigates how non-thermal plasma treatment alters water's mesoscopic structure, lowering the phase transition temperature and improving its physical properties for applications like produce washing.

Contribution

It demonstrates that plasma treatment shifts water's phase transition temperature and modifies its physical properties, supported by analytical estimates and experimental produce-washing results.

Findings

Plasma treatment lowers water's transition temperature.

Physical properties like surface tension and viscosity are significantly affected.

Enhanced produce washing efficacy observed.

Abstract

Recently is was discovered in various applications that many physical and chemical properties of water change their temperature dependence between about 35 and 60 degrees Celsius. In particular, heat conductance, light absorption, and surface tension all change their temperature dependence. These drastic changes were associated with water gradually changing its mesoscopic structure: while at the higher temperatures water is a uniform media (amorphous state), at the temperatures below transition it consists of many nano-to-micro-scale clusters (crystalline state). This transition is similar to the second order phase transition. In the present paper we show that treating water with non-thermal plasma (adding plasma-created active compounds) can lower the temperature of the transition and thus cause a significant change in such physical quantities as surface tension, viscosity, freezing rate, and wettability and washability. We present analytical estimates of the transition temperature shift based on the Debya-Huckel theory. We discuss the produce-washing experiments that illustrate the predicted effects.