A new device that uses wood dust to trap up to 99.9% of microplastics in water could be an answer to marine and freshwater pollution
Scientists at the University of British Columbia’s BioProducts Institute found that if you add tannins – natural plant compounds that make your mouth pucker if you bite into an unripe fruit – to a layer of wood dust, you can create a filter that traps virtually all microplastic particles present in water.
While the experiment remains a lab set-up at this stage, the team is convinced that the solution can be scaled up easily and inexpensively once they find the right industry partner.
Microplastics are tiny pieces of plastic debris resulting from the breakdown of consumer products and industrial waste.
Keeping them out of water supplies is a huge challenge, says Dr Orlando Rojas, the institute’s scientific director and the Canada Excellence Research Chair in Forest Bioproducts.
He noted one study which found that virtually all tap water is contaminated by microplastics, and other research which states that more than ten billion tons of mismanaged plastic waste will be dispersed in the environment by 2025.
He said: “Most solutions proposed so far are costly or difficult to scale up.
“We’re proposing a solution that could potentially be scaled down for home use or scaled up for municipal treatment systems.
“Our filter, unlike plastic filters, does not contribute to further pollution as it uses renewable and biodegradable materials: tannic acids from plants, bark, wood and leaves, and wood sawdust – a forestry byproduct that is both widely available and renewable.”
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Captures a wide variety of plastics
For their study, the team analysed microparticles released from popular tea bags made of polypropylene.
They found that their method (they’re calling it ‘bioCap’) trapped from 95.2%t to as much as 99.9% of plastic particles in a column of water, depending on plastic type.
When tested in mouse models, the process was proved to prevent the accumulation of microplastics in the organs.
Rojas, a professor in the departments of wood science, chemical and biological engineering, and chemistry at UBC, added that it was difficult to capture all the different kinds of microplastics in a solution, as they come in different sizes, shapes and electrical charges.
He said: “There are microfibres from clothing, microbeads from cleansers and soaps, and foams and pellets from utensils, containers and packaging. By taking advantage of the different molecular interactions around tannic acids, our bioCap solution was able to remove virtually all of these different microplastic types.”
And he advised: “Microplastics pose a growing threat to aquatic ecosystems and human health, demanding innovative solutions.
“We’re thrilled that the BioProducts Institute’s multidisciplinary collaboration has brought us closer to a sustainable approach to combat the challenges posed by these plastic particles.”
Image: Different types of wood waste can be used to create the water filter. Credit: UBC Forestry/ Jillian van der Geest. CC BY.
