Nigerian-born US varsity researcher optimises gas mixtures to degrade PFAS in water

A researcher at North Carolina State University (NCSU), Babatunde Michael Ojo, optimises the most effective gas mixtures for generating Vacuum Ultraviolet (VUV) radiation- a breakthrough that could improve the removal of PFAS (often called “forever chemicals”), which are difficult to destroy and pose serious environmental and health risks in contaminated water.

Ojo’s research characterises the VUV mechanisms within plasma-based water treatment by providing data from gas mixtures on how VUV radiation is produced and delivered. VUV radiation has remained a “black box” because it is readily absorbed by air, making it difficult to quantify the energy that actually reaches PFAS-contaminated water.

Using an atmospheric pressure plasma jet and a collisional-radiative model, Ojo determined the flux of VUV radiation for the gas mixtures. He calculated the densities of excited atomic species (oxygen, nitrogen, hydrogen, and helium) within the plasma. Three gas mixtures: Helium-Nitrogen, Helium-Water, and Helium-Water-Nitrogen were compared. The Helium-Water mixture produced the strongest VUV intensity, arising from helium resonance emission, which suppresses nitrogen. However, compared to other gas mixtures, the Helium-Water gas mixture minimizes nitrogen and controls water vapor, creating the strongest VUV flux.

Beyond determining the VUV intensity and flux, the study further examines how VUV radiation can be effectively transported from the jet to the PFAS-contaminated water via helium flow, without absorption by air.

Taken together, this research highlights the potential of plasma-based treatment systems to eliminate PFAS and safeguard the public water supply.