According to a story in Gizmag yesterday, a group of researchers at Newcastle University in the U.K. may have accidentally stumbled on a solution to the problems that have bedeviled carbon capture and sequestration — by studying sea urchins.
“We had set out to understand in detail the carbonic acid reaction, which is what happens when CO2 reacts with water, and needed a catalyst to speed up the process,” Dr. Lidija Šiller, the leader of the team, said in a press release. “At the same time, I was looking at how organisms absorb CO2 into their skeletons and in particular the sea urchin which converts the CO2 to calcium carbonate.”
The use of calcium carbonate to grow shells and other bony parts is a trait urchins share with other marine animals. And when the team examined the urchin larvae, they found a high concentrations of nickel on their exoskeleton. Working off that discovery, they added nickel nanoparticles to their carbonic acid test. The result was the complete removal of the CO2 as it was converted into calcium carbonate.
According to Gaurav Bhaduri, a PhD student in Newcastle University and the lead author of the team’s paper, the methodology they derived — and have now patented — is simpler and much cheaper than the traditional enzyme-based approaches:
“The beauty of a Nickel catalyst is that it carries on working regardless of the pH and because of its magnetic properties it can be re-captured and re-used time and time again. 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.”
The research team developed a process to capture CO2 from waste gas by passing it directly from a chimney top through a water column rich in nickel nanoparticles. The solid calcium carbonate can then be recovered at the bottom of the column.
The researchers say their discovery could provide big CO2 emitters, such as power stations and chemical processing plants, with a cheap way to capture and store their waste CO2 before it is released into the atmosphere.
Every method invented so far to capture or sequester carbon from emitters before it can enter the atmosphere has suffered from difficulties regarding cost, feasibility, and side-effects. Pumping CO2 into the ground, for instance, is difficult, expensive, and carries risks of leakage, water contamination, and even earthquakes. Other processes, like the ones mentioned by Bhaduri, also convert CO2 into calcium carbonate or magnesium carbonate through the use of enzymes like carbonic anhydrase. But because of the chemical complexities they’re inefficient and expensive.
Calcium carbonate, which is essentially chalk, is widely used in the building industry to make cement and other materials. It’s even used by hospitals to make plaster casts. So once removed from the Newcastle team’s carbon capture process, the calcium carbonate could potentially be put to other uses.
The discovery certainly isn’t a cure all. The process can’t be fitted to car, so its use is limited to power plants and other major emitters. But Dr. Šiller believes it could someday have a big impact: “It is an effective, cheap solution that could be available world-wide to some of our most polluting industries and have a significant impact on the reduction of atmospheric CO2.”
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