Researchers Fighting Plastic Pollution with Seaweed

D​r. Jianhua Zhang, a researcher from Victoria University (VU) studying plastic pollution, believes seaweed could be harnessed to replace one of the biggest contributors to waste in our oceans: plastic packaging. “We can’t live without plastic. It’s in our clothes, laptops, nearly every man-made organic product,” he says. However, “because crude oil will disappear someday and it’s not sustainable, we have to find something to replace it.”

Dr. Zhang has spent a decade studying polymers, such as plastic. And now his team has joined forces with colleagues in China to take their research beyond the lab.

Collaborating with China

China grows and harvests about three-quarters of the world’s seaweed annually, though not all of that seaweed is intended for eating. On the Shandong Peninsula, there are seaweed farms established exclusively for polymer production. Some have been used to make products including clothing.

That expertise makes China a crucial collaborator in the field of seaweed research. In this new project, Dr. Zhang’s team will work with three major universities across Shandong. Their plan is to recruit two Chinese or Australian students into their lab and run their research in parallel with their partners in China.

He says making the seaweed polymer will be only one part of the process; the other is to alter the polymer to suit specific products. He gives the example of PVC, one of the most common plastic polymers. Depending on how you modify the powder-like material, it can become either very rigid (and used for pipelines) or pliable (and used for wire insulation).

It’s a similar case with seaweed-based packaging, where the right additives can make the material stronger and more durable. Part of his project will examine more environmentally friendly chemicals that can be used in this process.

Both countries bring unique strengths, he says. “On the Australian side, we know how to modify those polymers for packaging purposes. On the Chinese side, they know how to extract the polymer from seaweed, and make those materials fit our requirements.”

Seaweed is in our Future

Dr. Zhang believes seaweed and other plants could replace plastic for good. “More than 70 per cent of our earth is the sea, so we have a great potential to farm plants in the sea to produce polymers,” he says. “These seaweed-based products could also help to tackle climate change by reducing our reliance on fossil fuels.”

Unlike crude oil, seaweed absorbs CO₂, leading some scientists to tout it as a carbon sink. One study found that seaweeds globally could sequester or store about 175 million tons of CO₂ annually. “If we can fix carbon in the air (from a gas to a solid), we’re going to reduce our greenhouse gas potential,” Dr. Zhang says. “So, if all our plastics originate from seaweed, that means we could fix millions, maybe billions, of tons of CO₂ currently in the air.”

Dr. Zhang hopes that his project will offer a blueprint for how seaweed research can be done.

Written by the Commonwealth Department of Foreign Affairs and Trade for the National Foundation for Australia-China Relations