Engineers at CEBC are searching for a better way to carry and deliver oxygen. They recently made nanoparticles that can bind to oxygen and release it when and where it's needed.
Just as your body needs oxygen, some industrial processes need it, too. The problem is storing this potentially explosive gas so that it can be released on demand.
CEBC researchers are working with a well known oxygen carrier called Co(salen). "Co" stands for the metal cobalt. This is the part that binds to oxygen. This carrier normally binds to oxygen only when dissolved in liquids. In solid phase, these complexes are not known to bind to any measurable amount of oxygen.
CEBC researchers recently developed a way to recrystallize Co(salen). It uses rapid precipitation with supercritical carbon dioxide as anti-solvent. This results in tiny rod-shaped nanoparticles that are 1000 times smaller than the diameter of a human hair -- like a grain of sand compared to the width of two parking spaces!
Shrinking the particle size "dramatically enhances oxygen binding capacity," said Bala Subramaniam, Director of CEBC. It distorts the shape of the molecule and makes the cobalt more accessible to oxygen. This is not the case in the original solid where the Co(salen) molecules stack up like Lego toys and block oxygen from binding.
The nanoparticles show reversible and near 1:1 binding to oxygen at room temperature. Most importantly, oxygen can be released with gentle heating.
Oxygen-carrying nanoparticles are easier and safer to transport than gas or liquid oxygen. And, they can carry more oxygen in a smaller space.
Although more research is needed before commercialization, these oxygen carriers could be used in various chemical and medical applications. They also might be useful in removing pollutants such as carbon monoxide or nitric oxide from the air.