Interactions between iron, water, oxygen and ions quickly become complex. MTU scientists
developed a more precise method to observe how iron minerals like rust form.
One can easily see with the naked eye that leaving an old nail out in the rain causes
rust. What does require the keen eyes and sensitive nose of microscopy and spectroscopy
is observing how iron corrodes and forms new minerals, especially in water with a
pinch of sodium and calcium.
Thanks to a new technique developed by chemists at Michigan Technological University,
the initial stages of this process can be studied in greater detail with surface analysis.
The team, led by Kathryn Perrine, assistant professor of chemistry, recently published their latest paper in The Journal of Physical Chemistry A.
The group’s main finding is that the cation in solution — positively charged sodium
or calcium ions — influences the type of carbonate films grown when exposed to air,
which is composed of atmospheric oxygen and carbon dioxide. The gradual exposure of
oxygen and carbon dioxide produces carbonate films specific to the cation. The iron
hydroxides of different shapes and morphologies are without gradual air exposure,
not specific to the cation.
A better understanding of this process and how fast the minerals form opens up possibilities
for monitoring carbon dioxide capture, water quality byproducts and improving infrastructure
management for old bridges and pipes.
Play Chemists Watch Rust Form video
Chemists Watch Rust Form
Interactions between iron, water, oxygen, and ions quickly become complex. Studying
the air-solution-solid interface is tricky, which is why chemist Kathryn Perrine led
a team to develop a more precise, three-step method to observe how iron minerals like
rust form. Republished with permission from The Journal of Physical Chemistry A. Copyright
2021 American Chemical Society.
Read more:: Surface Chemistry Reveals Corrosive Secrets