Researchers from the University of Southern Denmark have devised a new class of materials that can bind and store oxygen in high concentrations.
According to the researchers, just one spoon of the synthesized crystalline material is enough to absorb all the oxygen in a room. The stored oxygen can be released again when and where it is needed.
Unlike many substances that react adversely with oxygen – such as food going rancid when exposed to oxygen or a wine’s taste and aroma changing subtly when it is aerated – the synthesized material shows no signs of such reaction.
“An important aspect of this new material is that it does not react irreversibly with oxygen – even though it absorbs oxygen in a so-called selective chemisorptive process. The material is both a sensor, and a container for oxygen – we can use it to bind, store and transport oxygen – like a solid artificial hemoglobin”, says Christine McKenzie, a professor from the university’s Department of Physics, Chemistry and Pharmacy.
The material is so effective at binding oxygen, that only a spoon of it is enough to suck up all the oxygen in a room. The researchers’ work indicates that the substance can absorb and bind oxygen in a concentration 160 times larger than the concentration in the air around us.
“It is also interesting that the material can absorb and release oxygen many times without losing the ability. It is like dipping a sponge in water, squeezing the water out of it and repeating the process over and over again”, Christine McKenzie explains.
Once the oxygen has been absorbed it can be stored in the material until one wants to release it. The oxygen can be released by gently heating the material or subjecting it to low oxygen pressures.
“We see release of oxygen when we heat up the material, and we have also seen it when we apply vacuum. We are now wondering if light can also be used as a trigger for the material to release oxygen – this has prospects in the growing field of artificial photosynthesis”, says Christine McKenzie.
The key component of the new material is the element cobalt, which is bound in a specially designed organic molecule.
“Cobalt gives the new material precisely the molecular and electronic structure that enables it to absorb oxygen from its surroundings. This mechanism is well known from all breathing creatures on earth: Humans and many other species use iron, while other animals, like crabs and spiders, use copper. Small amounts of metals are essential for the absorption of oxygen, so actually it is not entirely surprising to see this effect in our new material”, explains Christine McKenzie.
Apart from being used extensively in the medical field, stored-up oxygen is also used across a wide range of industries including aerospace, oil & gas as well as automotive. Oxygen is used as a plasma cutting gas, an assist gas for laser cutting, and is sometimes added in small quantities to shielding gases in the auto manufacturing process.
Using oxygen in the place of air can increase performance and capital efficiency in many industries and can enable carbon capture processes. It is often used in boilers and process heaters, industrial fermenters and gasification processes to improve productivity. As an industrial gas, oxygen is used to replace or enrich air, ultimately increasing combustion efficiency in both ferrous and non-ferrous metal production.
Talking about the energy sector, oxygen is widely used in refineries to increase the capacity of Fluid Catalytic Cracking (FCC) plants and Sulfur Recovery Units (SRU), and to improve wastewater treatment operations.
The same holds true with the aerospace and aircraft industry; ever since the early 1960s, oxygen in its liquidized form has been utilized to prepare and launch many bipropellant vehicles, apart from being used to support rocket fuel combustion.
Image courtesy of University of Southern Denmark