Fluorinated membrane breaks a limit for capturing carbon dioxide
Carbon dioxide is an all too common waste product of industry, belched into the air in huge amounts from smokestacks. Now, researchers have developed a new type of fluorinated membrane that can selectively filter CO2 out of flue gas at the point of release.
Carbon capture is a promising avenue of research to help slow the march of climate change, preventing greenhouse gases from being released in the first place. To this end, scientists are exploring many different technologies, including clay, bubble-like membranes, ionic liquids, metal-organic frameworks, and porous powders.
The new study, by researchers at Oak Ridge National Laboratory and the University of Tennessee, builds on one of the simplest forms of carbon capture: polymer membranes. These can be stretched across a facility’s chimney where they selectively filter carbon dioxide out of flue gas, while allowing gases like oxygen and nitrogen to escape into the atmosphere.
The secret ingredient of the team’s new membrane is fluorine. This element bonds particularly strongly to carbon, making it an attractive option for carbon capture. The researchers started with a fluorine-based polymer, then heated it to carbonize it. This gives the material a porous structure while maintaining the fluorinated groups, which boosts how much it selects for CO2.
“The approach resulted in a carbon dioxide-philic material with high surface area and ultra-micropores that is stable in high-temperature operating conditions,” says Zhenzhen Yang, first author of the study. “All of these factors make it a promising candidate for carbon-capture and separation membranes.”
Normally, membranes like this have a trade-off between selectivity for certain gases, and permeability – as one goes up, the other goes down. But the team says that the fluorine-based membrane balances the two properties well, breaking what’s known as the Robeson upper limit. Few materials have achieved this, the team says.
Better yet, fluorine and the other starting materials are abundant and inexpensive, and the process to make them is simple, which will help in scaling up.
In future work, the team plans to further investigate the mechanism for fluorine’s CO2 selectivity, and try to improve the recipe further.
The research was published in the journal Chem.
Source: Oak Ridge National Laboratory
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This whole issue reminds me of a 60 minutes episode 25 years ago. A company developed a pollution detection device and offered to sell it for $100k each to the government. Congress was on board. A scientist caught wind of it and developed the same device for under $10 with a coffee can. The whole project was dropped.
Congress wasn't interested in a solution, they were only interested in the campaign kickbacks, oops, contributions.
These CO2 capture schemes are pushed and developed for fossil fuel industries. They make good press and give people the impression global warming will be solved. But it won't work that way.
We need to take carbon gas from the air and turn it into carbon solids. The only way to do that cost effectively is through pyrolysis of organic material. But that only benefits farmers. So that solution is dropped.
Anyone who believes that CO2 causes climate change, is, well, misinformed, and gullible. It has not done so during the last 600 million years. It is a vast political scam.
As for warming, the planet is presently, and throughout this present glacial period, the coldest it has been since the Permian extinction, 270 million years ago, and it will get colder, a lot colder.
The planet orbits the sun, but the solar system orbits the centre of the galaxy, independently from the rotation of the galaxy, with a period of around 600 million years. 600 million years ago, the planet exited an ice age that is called the ''Snowball Earth'' event, when the planet was totally covered in ice, and all life, except bacteria and similar organisms was extinguished. The ice ages occur at approximately 150 million year intervals and last for tens of millions of years. They are caused by the solar system passing through the arms of the galaxy, and interstellar dust attenuating the suns radiation reaching the planet. The present ice age, started more than 40 million years ago, and could well be a repeat of the Snowball Earth event.
So, a warming planet is of no consequence, the biggest danger to all life is a cooling planet, like now.
However, a membrane-based carbon capture approach is basically doomed to fail, given the particulate matter that accompanies fossil-fueled products of combustion (PM2.5, black soot, sulfurous particles, etc.)
A further, cost-related problem with this fluorinated membrane-based approach can be evidenced by examinining the PEM hydrogen fuel cell arena. Today these PEM fuel cell devices usually use Nafion, a fluorinated polymer membrane, which is very expensive. Many teams are trying to replace Nafion with a lower-cost, but well-performing non-fluorinated membranes. To-date, nothing has broken through.
At least they got a publication in a good journal...