Unlike the window screens on a house, nanoscale holes in graphene (named as “nanowindows”) can selectively choose which type of air molecules can pass through.
“Scientists from Shinshu University and PSL University, France, theoretically proved concerted motion of the nanowindow-rim to selectively allow molecules to pass, in an energy-efficiently and fast way. This brings up new possibilities to create an advanced molecular separation membrane technology.”
Nanowindows were prepared by oxidation treatment. Thus their rims are passivated with hydrogen and oxygen atoms, which have essential role for selective permeation.
Surprisingly, the molecules permeate through nanowindows even when the rigid nanowindow size is smaller than the target molecular size. For example, O2 permeates faster through 0.29nm nanowindows than 0.33nm nanowindows. The difference in permeation rate is associated with the interaction of the molecule with the nanowidow rim and graphene. The mechanism is explained using interaction energy and vibrational motion of the oxygen and hydrogen at the nanowindow rim….
Air separation in current industry uses distillation, which consumes large amount of energy. Gases used in this study are widely employed in various industries such as medical, food, steal, etc. Development of the dynamic nanowindows-embedded graphenes will save large amount of energy and provide safer and high efficient process. This study shows the future direction of air separation”.
New mechanisms discovered to separate molecules of air
Source: Alerts – Shinshu University See also