Turning ordinary water into a disinfectant

STUDENT PROJECT - For his semester’s project, Constant Panisset is developing a cheap, robust and portable device that can turn water into a disinfectant via the principle of plasma activated water. The device could be a solution for disinfecting hospital equipment in developing countries. He is currently investigating the possibility of sending his device into space.

Imagine a cheap, robust and portable device that can turn ordinary water into a disinfectant in less than a minute. That’s exactly what Constant Panisset is working on for his physics semester project at the Swiss Plasma Center in the laboratory of Ivo Furno, using the principle of plasma activated water with the added complication that the device must work in space.

“I am passionate about plasma physics, and I wanted to gain experience in this field that has industrial applications,” says Panisset, a Master’s student at EPFL. “Plasma activated water has the potential to simplify the lives of many because it’s easy to scale-up.”

Plasma physics is a vast field of research with already many applications, and at the outset, Panisset considered several options. “Fusion for energy production with a reactor is promising but not yet ready for industrial scales,” explains Panisset. “Aerospace plasmas accidentally discharged from a satellite’s solar panel can potentially destroy or decommission satellites. Plasmas are also used to propel rockets or satellites once in space. Plasmas are also used to etch smaller and more precise electronic components.”

A passion for plasma physics, and also a keen interest for hands-on experience, Panisset is a member of the EPFL Rocket Team. When it came time to think of a semester project, he looked into the possibility of combining plasmas and space.

Disinfectant properties of plasma activated water

It’s the disinfectant properties of plasma activated water that caught his interest and ticked all the right boxes : industrial applications, helping people, and the added challenge of trying to make a device that works in close to zero gravity.

To make plasma activated water, one first needs to make a plasma, which essentially means taking a gas and ripping off the electrons from its particles to create ions. When this plasma is exposed to water, the acidity of the water increases while its composition changes so that water (H20) now contains new species like hydrogen peroxide (H2O2), nitrites (NO2) and nitrates (NO3). Plasma activated water is known to kill off bacteria and has applications in agriculture, medical appliances and hygiene in general.

Engineering plasma activated water for extreme conditions

But there are many ways to make activated water, and Panisset wanted to engineer the most robust way to do this, either for the medical community in developing countries or for being sent into space. He opted for a device that creates a strong potential across both air and water, placing one electrode in the air and another one in the water. But for making a small device that can work in space, he still has to optimize the dimensions, the strength of the potential, and encase it all so that any accidental discharges are contained for safety reasons.

“Engineering plasma activated water in microgravity is interesting because, if we can make it work, then with only water and a bit of electricity, it could prevent the propagation of illnesses on future spaceships or lunar bases like Artemis.”

The device is planned to be on board EPFL Rocket Team’s Nordend Rocket, to be launched in October 2023.

Author: Hillary Sanctuary

Source: EPFL

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