The toll of pandemic-related plastic waste from discarded personal protective equipment is mounting at an alarming rate. Health Canada estimates that between June 2020 and June 2021, 63,000 tons of COVID-19 related PPE will end up as landfill waste in this country alone.

Which is why researchers are investigating possibilities for disinfecting and reusing single-use PPE, including medical gloves and hospital gowns.

At the University of Waterloo, chemical engineer Tizazu Mekonnen recently discovered that disposable gloves can be safely reused up to 20 times if disinfected using alcohol, ultra violet (UV) radiation or dry-heat treatments.

Mekonnen decided to look into the possibility after a visit to his local Walmart early in the pandemic. “That was a crazy time – there was a shortage of gloves,” he recalls.

The pharmacist told him she and her staff were disinfecting their gloves and reusing them. When he asked if it was safe, she said she didn’t know but had no choice.

“I’m a polymer scientist and I kept thinking about that,” says Mekonnen. “So I went back to my lab to see how far we could push the disinfection cycle.”

Examining chemical changes and barrier properties

He and his team studied six viral disinfection treatments on two types of disposable gloves commonly worn by health-care workers and others to guard against COVID-19.

They evaluated the effects of disinfecting gloves made from nitrile and ones made from latex. They used UV, dry heat, steam, alcohol, chlorine compounds, and quaternary ammonium compounds, commonly found in disinfectant wipes, sprays and other household cleaners designed to kill germs.

They tested the gloves’ material for changes to its chemical structure and baseline strength. They also tested its ability to keep out water. “When you think about blood and other bodily fluids, they contain a high concentration of water,” says Mekonnen.

The found that either type of glove could withstand up to 20 cycles of the six types of disinfection treatments with no change to its chemical structure and little to no change to its baseline strength. But only the alcohol, UV and dry-heat treatments did not affect the barrier properties of the gloves when they were disinfected between 10 and 20 times.

The researchers found that when steam, chlorine compounds and quaternary ammonium compounds were used 20 times, there was a slight reduction in the gloves’ barrier properties. This was true even though the gloves’ chemical structure and baseline strength didn’t change.

“That’s because if you change the way the chains of the polymer are entangled in the rubber, the barrier properties will change as a result,” said Mekonnen.

He hopes his findings will help inform the responsible reuse of gloves and suggests alcohol is likely the most promising treatment because it’s already widely used as a disinfectant in health-care settings.

Clean produce, clean hospital gowns

Meanwhile, University of Guelph researchers are looking into ways to reuse isolation gowns from hospitals and health centres by refining technology traditionally used for cleaning produce, such as apples and peaches.

The process uses forced air to blow ozone through batches of gowns inside a metal chamber. Project partners include Clean Works Corp., based in Beamsville, Ontario, and Mohawk Medbuy Corp. in Hamilton. Mohawk Medbuy launders linens from nearly 50 health-care sites nationally, including about 120,000 isolation gowns per week.

“This ozone technology could replace washing and save not only energy and water but also increase the throughput of gowns long after the pandemic is over,” food scientist Keith Warriner said in a release.