In yet another example of scientific serendipity, Uppsala University researchers have created an unprecedented material with record-breaking properties. And most remarkable of all, this new material — which was thought impossible to make for over a century — was the result of an accident in the lab.
And indeed, the new magnesium carbonate material exhibits some remarkable properties.
Adsorption, Not Absorption
Called upsalite in honor of the university where it was discovered, the material features a surface area of 800 square meters per gram. It's got the highest surface area measured for a synthesized alkali metal carbonate. And in addition, upsalite is filled with empty pores all having a diameter smaller than 10 nanometers.
This means that it can absorb — or more accurately, adsorb — more water at low relative humidities than the most advanced materials currently in existence.
Unlike absorption, where fluids permeate or are dissolved by a liquid or solid, adsorption involves the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface. And it does so as a consequence of surface energy (similar to surface tension).
a) Scanning electron microscope view of upsalite. Scale bar, 1 µm. b) Higher magnification SEM of a region in a) showing the textural porosity of the material. Scale bar, 200 nm. c) image of upsalite showing contrast consistent with a porous material. The image is recorded with under-focused conditions to enhance the contrast from the pores. Scale bar: 50 nm.
Once refined, upsalite could significantly reduce the amount of energy required to control environmental moisture in electronics and in drug delivery. It could also be used in hockey rinks and warehouses. Perhaps more crucially, the material could be used to suck up toxic waste, dangerous chemicals, and oil spills.
Scientists have known about natural and ordered forms of magnesium carbonate, both with and without water structure, for quite some time. But creating a water-free disordered version has proven difficult. As early as 1906, German researchers concluded that the material could not be created in the same way as other disordered carbonates, namely by bubbling C02 through an alcoholic suspension. Other studies in 1926 and 1961 came to the same conclusion.
'We started to get excited'
But on one fateful Thursday afternoon in 2011 this all changed. A research team led by Johan Goméz de la Torre made some slight changes to the synthesis parameters of an earlier unsuccessful attempt to create a water-free disordered form of magnesium carbonate — and they left it in the reaction chamber by mistake! It sat there for the entire weekend, and when the researchers returned to the lab the following Monday, a rigid gel had formed.
Surprised and excited, they dried the gel and studied it further. They soon realized that they were onto something.
After a year of further experiments and refinements, upsalite was born. The new material featured an adsoprtion capacity about 50% larger than that of comparable materials at low relative humidities, and an ability to retain more than 75% of the adsorbed water when the humidity was decreased from 95% to 5% at room temperature.
“This places the new material in the exclusive class of porous, high surface area materials including mesoporous silica, zeolites, metal organic frameworks, and carbon nanotubes”, noted researcher Maria Strømme through a release. Indeed, it can adsorb more water at low humidities than the best materials available — and with less energy. “This, together with other unique properties of the discovered impossible material is expected to pave the way for new sustainable products in a number of industrial applications”, said Strømme.
Read the entire study for free at PLoS ONE: "A Template-Free, Ultra-Adsorbing, High Surface Area Carbonate Nanostructure.”
Images: Goméz de la Torre et al./PLoS