EnlargePosted on 08/15/2013 8:47:20 AM PDT by neverdem
Credit: Simon Ydhag, Uppsala University
Credit: Simon Ydhag, Uppsala University
Researchers in Uppsala, Sweden accidentally left a reaction running over the weekend and ended up resolving a century-old chemistry problem. Their work has led to the development of a new material, dubbed Upsalite, with remarkable water-binding properties. Upsalite promises to find applications in everything from humidity control at home to chemical manufacturing in industry.
Maria Strømme and colleagues at Uppsala University, whose work appears in the journal PLOS ONE, have modified a procedure dating back to 1908 to make a powdered and dry form of magnesium carbonate (MgCO3). The reaction ingredients are all cheaply available: magnesium oxide (MgO) and carbon dioxide (CO2), dissolved in methanol, a common industrial solvent. The result is pure, dry MgCO3.
Dry in this case means very dry. In the chemical sense, it means void of almost any water molecules at all.
Crystalline forms of dry MgCO3, which lack the structure needed to absorb water, are readily synthesised at high temperatures (over 100 °C). As early as 1820, people started to search for lower-temperature routes to make dry MgCO3, but none have successfully yielded pure product until now. This is why Upsalite has been described as an "impossible material".
The key modification was to increase the pressure of CO2 to three times that of normal atmospheric pressure, rather than simply bubbling the gas through a mixture of MgO in methanol. When one mixture was accidentally allowed to react over a long weekend, researchers came back to find a gel. It turns out the gel was formed because methanol molecules had been trapped within the material. When heated to 70 °C, which is above the boiling point of methanol, the gel "solidifies and collapses into a white and coarse powder". Analysis confirmed that the product was just what chemists had been trying to make for more than 100 years – a dry, powdered form of MgCO3.
Upsalite has impressive properties as a desiccant, absorbing water better than the much more expensive materials that are currently used (called zeolites). Most of the absorbed water is retained when Upsalite is transferred from a humid to a very dry environment. The dry form can be regenerated by heating to 95 °C. By contrast, most zeolites need to be heated to over 150 °C in order to dry them. Not only is Upsalite easy to make and reuse, but it is also not toxic to humans, which makes it suitable for humidity control indoors.
The impressive drying property stems from the very large internal surface area of Upsalite. MgCO3 is a common mineral that occurs in a variety of forms, most of which have water bound to their surface and are crystalline. By contrast, Upsalite has no water integrated into its structure and is not crystalline. Instead, it is mesoporous – a structure with pores that are a million times smaller than the width of a human hair – which provide it with a much greater surface area.
The past 20 years have seen a surge of interest in mesoporous materials such as zeolites and carbon nanotubes due to their ability to selectively absorb small molecules, which may enable applications in drug delivery, pollution removal, and the development of new catalysts for chemical reactions. Recognizing these prospects, the researchers have founded a spin-out company called Disruptive Materials to commercialise and apply Upsalite.
More information: Forsgren J, Frykstrand S, Grandfield K, Mihranyan A, Strømme M (2013) A Template-Free, Ultra-Adsorbing, High Surface Area Carbonate Nanostructure. PLoS ONE 8(7): e68486. DOI: 10.1371/journal.pone.0068486
Abstract
We report the template-free, low-temperature synthesis of a stable, amorphous, and anhydrous magnesium carbonate nanostructure with pore sizes below 6 nm and a specific surface area of ~ 800 m2 gm-1, substantially surpassing the surface area of all previously described alkali earth metal carbonates. The moisture sorption of the novel nanostructure is featured by a unique set of properties including an adsorption capacity ~50% larger than that of the hygroscopic zeolite-Y at low relative humidities and with the ability to retain more than 75% of the adsorbed water when the humidity is decreased from 95% to 5% at room temperature. These properties can be regenerated by heat treatment at temperatures below 100°C.The structure is foreseen to become useful in applications such as humidity control, as industrial adsorbents and filters, in drug delivery and catalysis.
Source: The Conversation
This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives).
They also invented Upsaladasium - it has anti-grav properties.
Rocky and Bullwinkle bump!
And Glenn Beck can sell you some Carbonite to keep your Upsaladasium secure.
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It's amazing how many discoveries have been stumbled upon--scientists who discover America while looking for India.
I was hoping for transparasteel, or maybe even Unobtanium.
I can just see the little packets of dessicant made from this in the near future labeled "GO AHEAD AND EAT"
Has anyone been about to produce solarmanite?
There’s a lot to be said for forgetting to turn off the machine at night.
It’s also how modern chocolate came about...
This will have significant impact in the drying of Ethanol.
Here in Silicon Valley, it would be an easy mistake to make...
Couldn’t you just dissolve magnesium in carbonic acid, then boil off the supernatant? I realize that would leave the crystalline MgCO3 — not the amorphous anhydrate — but couldn’t you get there by driving the water off and reducing the crystals by physical grinding?
“And Glenn Beck can sell you some Carbonite to keep your Upsaladasium secure.”
in a Liberty safe - you forgot that part.
Forgive me. It was too sweet to pass up.
Guarded by Dolomite.
This is interesting and perfectly credible, IMO. I’m not sure how important dessicants are, but they may be very useful in the case of water damage to houses (remove any excess water, pour the mag-oxide over the rugs, leave x minutes, and then just vacuum up the powder).
While eating Vegamite.
"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'" - Isaac Asimov
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