Newcastle University sea urchins studies hold key to global emissions

THE humble sea urchin has shown the way for North East scientists to find a potentially simple solution for one of the biggest environmental issues of our times.

Professor Lidija Siller and Gaurav Bhaduri, PhD student, at Newcastle University
Professor Lidija Siller and Gaurav Bhaduri, PhD student, at Newcastle University

THE humble sea urchin has shown the way for North East scientists to find a potentially simple solution for one of the biggest environmental issues of our times.

The chance discovery was made by Newcastle University physicist Dr Lidija Siller as she studied the sea creature.

She found that sea urchins use nickel particles to harness carbon dioxide from the sea to grow their exoskeleton.

And that could be the key to capturing tonnes of carbon dioxide from the atmosphere.

Now the experts at Newcastle have discovered that in the presence of nickel, CO2 can be converted rapidly and cheaply into the harmless, solid, mineral, calcium carbonate, or chalk.

The breakthrough has the potential to revolutionise the way carbon is captured and stored, while at the same time producing a useful material.

This could significantly reduce CO2 emissions, the key greenhouse gas responsible for climate change.

Chalk makes up around 4% of the Earth’s crust and acts as a carbon reservoir, estimated to hold the equivalent to 1.5 million billion metric tons of carbon dioxide.

It is the main component of shells of marine organisms, snails and pearls, as well as eggshells. It is a completely stable mineral and is used to make products ranging from cement to hospital plaster casts.

Dr Siller, a reader in nanoscale technology at Newcastle University, said it would be “remarkable” if the process could be developed on a factory scale.

She had been studying sea urchins for two years, looking at how they grow their bony parts.

“When we analysed the surface of the urchin larvae, we found a high concentration of nickel on their exoskeleton,” said Dr Siller.

“Taking nickel nanoparticles which have a large surface area, we added them to a carbonic acid test and the result was the complete removal of CO2.”

At the moment, pilot studies for Carbon Capture and Storage systems propose the removal of CO2 by pumping it into holes deep underground, such as mine cavities or voids left by oil extraction.

But this is a costly and difficult process, and carries with it a long-term risk of the gas leaking back out, possibly many miles away from the original, downward source.

An alternative solution is to convert the CO2 into calcium or magnesium carbonate.

“One way to do this is to use an enzyme called carbonic anhydrase,” said Gaurav Bhaduri, lead author on the study and a PhD student at Newcastle University’s School of Chemical Engineering and Advanced Materials.

But the enzyme is only effective for a very short time and the process is very expensive. “The beauty of a nickel catalyst is that it carries on working regardless and because of its magnetic properties, it can be re-captured and re-used time and time again,” said Mr Bhaduri.

“It’s also very cheap – 1,000 times cheaper than the enzyme – and the by-product, the carbonate, is useful and not damaging to the environment. What our discovery offers is a real opportunity for industries such as power stations and chemical processing plants to capture all their waste CO2 before it ever reaches the atmosphere and store it as a safe, stable and useful product.”

Each year, humans emit on average 33.4bn metric tons of CO2, around 45% of which remains in the atmosphere. Typically, a petrol-driven car will produce a ton of CO2 every 4,000 miles.

The process developed by the Newcastle team involves passing the waste gas directly from the chimney top, through a water column rich in nickel nano-particles and recovering the solid calcium carbonate from the bottom. Dr Siller said: “The capture and removal of CO2 from our atmosphere is one of the most pressing dilemmas of our time.

“Our process would not work in every situation – it couldn’t be fitted to the back of a car, for example – but it is an effective, cheap solution that could be available worldwide to some of our most polluting industries and have a significant impact on the reduction of atmospheric CO2.”

The team have patented the process and are now looking for an investor to take it forward.

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