Magnetic invention removes microplastics and some PFAS from wastewater

RMIT University researchers say they have developed a magnetic material that rapidly removes micro and nano plastics and some PFAS from water, bringing the technology closer to real world use.

The invention, a dark adsorbent material that can be added to wastewater and separated with a magnet, builds on the team’s 2022 research in microplastics removal, extending performance to much smaller particles and more complex wastewater.

Microplastics are an increasing global concern, with growing evidence of their presence in water systems. The researchers say the ability to remove micro‑ and nano‑plastics under practical conditions sets this work apart.

Tests also showed removal of large molecules of PFAS compounds, which researchers say may be another promising application, though that part remains at an early stage.

In lab testing, the material removed more than 95% of micro‑ and nano‑plastics, including particles as small as 30 nm, within one hour. The material also removed more than 95% of tested contaminants including mercury, chromium, copper, dyes and ibuprofen.

About 80% were removed in the first 15 minutes, aligning with contact times used in treatment plants. The material performed across common plastics such as polyethylene, polypropylene and polyester, and in both fresh and saline water.

The team tested the material in industrial laundry wastewater, a major source of microplastic pollution from synthetic fibres. It removed more than 88% of polyester microfibres along with dyes, maintaining performance despite surfactants and organic matter.

A prototype system combining the adsorbent with magnetic separation technology from One Eye Industries in Canada showed the material could be recovered quickly after treatment and reused.

Roger Simonson, founder and inventor of One Eye Industries, said recovery of treatment material remained one of the biggest barriers to bringing new water treatment technologies out of the laboratory.

“Industry has been waiting for a practical way to move microplastics and emerging contaminants removal out of the laboratory and into real treatment environments,” he said. “The challenge isn’t only capturing these particles, it’s recovering the treatment material quickly and reliably after it has done its job, without creating a new waste stream.

“Combining high-performance pollutant capture with proven magnetic separation creates a much stronger pathway to real‑world deployment.”

The team is working with Indigenous‑owned company Fire and Test Australasia, based in Geelong, Victoria, to explore the possibility of treatment of stormwater and wastewater, including in community settings.

Lead researcher Professor Nicky Eshtiaghi from the School of Engineering said the partnership reflected a shared focus on water stewardship.

“Cleaning and protecting water are deeply important for Indigenous communities as custodians of land and waterways,” she said.

The researchers are also collaborating with Australian company Star Water Group, which has clients in the United States, including California, where tightening regulations are increasing demand for improved microplastics treatment.

Simonson said the technology showed strong potential for textile and industrial wastewater, municipal treatment systems, stormwater and decentralised water treatment.

“Professor Eshtiaghi and her team have brought deep scientific expertise and a clear grasp of the operational challenge, and we see real potential for this technology in textile and industrial wastewater, municipal treatment and other settings where microplastics and co-contaminants defeat conventional approaches,” he said.

Since 2022, the team expanded the material’s capability, capturing particles from nanoscale plastics through to larger fibres while also removing dissolved contaminants in the same process.

Testing showed up to 90% removal of mixed contaminants, with complete removal of fibres in textile wastewater.

Output increased fivefold through a room‑temperature manufacturing process using fewer costly inputs. Early analysis suggested costs reduced by about 75% compared to earlier versions. The material can also be reused multiple times, supporting cost‑effective use.

The paper ‘Scalable room-temperature synthesis of a MOF-based magnetic adsorbent for rapid simultaneous removal of PFAS and micro-nanoplastics’ is published in Chemical Engineering Journal.

Image: Professor Nicky Eshtiaghi holds a vial containing the team's magnetic adsorbent material designed to remove microplastics, nanoplastics and other contaminants from water. Credit: Will Wright, RMIT University