Plasma water, also known as plasma-activated water (PAW), is created by treating ordinary water with plasma. This process imbues the water with unique properties. It is gaining recognition across various sectors, from agriculture to medicine, for its potential to offer effective and environmentally conscious solutions.
What is Plasma Water
Plasma water is water altered by exposure to plasma, an ionized gas. This interaction introduces highly reactive chemical species, primarily reactive oxygen species (ROS) and reactive nitrogen species (RNS). These species include compounds like hydrogen peroxide, nitrite, and nitrate, which are not typically found in significant concentrations in regular water. The presence of these reactive compounds gives plasma water its distinctive characteristics, such as altered pH, redox potential, and electrical conductivity. While these reactive species are stable in the water for a period, their transient nature means they eventually degrade, returning the water to its original state. This temporary modification provides plasma water with its unique functional properties.
Creating Plasma Water
Plasma water is generated using cold plasma technology, which energizes a gas to create plasma at near-room temperatures. Plasma is the fourth state of matter, formed when enough energy is added to a gas to ionize its atoms, stripping away electrons and creating a mixture of ions and electrons. This process can mimic natural phenomena, such as lightning, which also generates reactive compounds in the atmosphere.
Common techniques for producing plasma water include atmospheric pressure plasma jets, dielectric barrier discharges (DBD), and gliding arc discharges. In these methods, an electrical field is applied to a gas, often air, transforming it into plasma. This plasma then comes into contact with water, transferring its energy and reactive species into the liquid, creating plasma-activated water.
Applications of Plasma Water
Plasma water demonstrates diverse practical uses across multiple sectors due to its unique properties. In healthcare and medicine, it shows promise for wound disinfection and the sterilization of medical equipment. Its bactericidal properties are being explored for root canal disinfection and therapeutic uses in dermatology and wound healing.
In agriculture, plasma water impacts crop production. It is used for seed treatment to enhance germination and promote improved sprouting. Furthermore, it stimulates overall plant growth and can provide protection against plant pathogens, offering an alternative to traditional chemical pesticides. Plasma water can also clean and sterilize water for produce washing and disinfection before packaging, extending shelf life.
The food industry also benefits from its antimicrobial capabilities. It can sterilize food surfaces and decontaminate fresh produce, reducing pathogens and spoilage organisms. This enhances food safety and extends shelf life.
For water treatment, plasma water is being investigated for disinfecting contaminated water and removing pollutants, including organic and micro-pollutants like pharmaceuticals, without additional chemicals or filters.
The Science Behind Plasma Water
The unique properties of plasma water arise from the reactive oxygen species (ROS) and reactive nitrogen species (RNS) generated during plasma treatment. These short-lived, highly reactive molecules include hydrogen peroxide (H2O2), hydroxyl radicals (∙OH), ozone (O3), nitrite (NO2-), and nitrate (NO3-). Their specific concentrations can be adjusted by altering the electrical discharge type, gas composition, and water properties during production.
These reactive species interact with biological materials in various ways. For instance, in disinfection applications, ROS act as strong oxidizing agents that can induce oxidative stress on microbial cell membranes, leading to their disruption and inactivation. The combination of these reactive species and the often-lower pH of plasma water contributes to its broad-spectrum sterilization efficacy. In agriculture, RNS can participate in various signaling pathways within plants, influencing metabolic processes, plant development, and responses to stress. This can lead to enhanced seed germination, improved root development, and increased overall plant growth.