With carbon dioxide emissions continuing to rise and drive up global temperatures, many scientists are pursuing technologies that can capture the gas before it enters the atmosphere. Scientists at Newcastle University have happened upon a particularly promising example, developing a low-cost membrane that assembles one of its own key components as it absorbs CO2.
Over the years we have looked at many interesting examples of how we might capture human-generated CO2 at the source. These range from edible sponges, to molten salts, to naturally occurring bacteria, all framed as potential options when it comes to reigning in excess atmospheric carbon dioxide and helping combat the effects of climate change.
In developing its solution, the Newcastle University team took a previously untried approach of developing a self-assembling membrane. In its final form, this would work much like a coffee filter, separating harmless gases like nitrogen from carbon dioxide, which can then be collected and processed for other uses.
A key part of this membrane is silver, but rather than integrating the required amount of the material and in the correct shape, the team wanted to see if they could start with a small amount of it instead. Tiny pellets and tubes of aluminum oxide were used as supports for the membrane, and then a tiny amount of silver was added to the mix.
As carbon dioxide and oxygen permeated the membrane, it stimulated the self-assembly of silver dendrites, or branch-like structures, with the material continuing to disperse within the structure as it continued to operate. This process was confirmed via X-ray micro-computed tomography, with the self-assembling membrane proving capable of a competing with existing technologies, but with potentially much lower costs.
“These savings are important – the cost of carbon capture is one of the key factors limiting uptake of the technology. There is a common metric for membrane performance – the “upper bound.” As our membrane relies on a unique transport mechanism, we avoid the limitations of most membrane materials and go far beyond the upper bound! We hope that this study inspires new ways to form membranes, that lower costs, as well as drives interest in this new class of membrane for future application to protect our environment.”
The research was published in the journal Energy and Environmental Science.
Source: Newcastle University