Anomalous water expulsion from carbon-based rods at high humidity.
Three water adsorption-desorption mechanisms are common in inorganic materials: chemisorption, which can lead to the modification of the first coordination sphere; simple adsorption, which is reversible; and condensation, which is irreversible. Regardless of the sorption mechanism, all known materials exhibit an isotherm in which the quantity of water adsorbed increases with an increase in relative humidity. Here, we show that carbon-based rods can adsorb water at low humidity and spontaneously expel about half of the adsorbed water when the relative humidity exceeds a 50-80% threshold. The water expulsion is reversible, and is attributed to the interfacial forces between the confined rod surfaces. At wide rod spacings, a monolayer of water can form on the surface of the carbon-based rods, which subsequently leads to condensation in the confined space between adjacent rods. As the relative humidity increases, adjacent rods (confining surfaces) in the bundles are drawn closer together via capillary forces. At high relative humidity, and once the size of the confining surfaces has decreased to a critical length, a surface-induced evaporation phenomenon known as solvent cavitation occurs and water that had condensed inside the confined area is released as a vapour.
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Satish K
0000-0002-2971-0554
SK
Nune
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
David B
DB
Lao
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
David J
DJ
Heldebrant
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Jian
0000-0001-5329-7408
J
Liu
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Matthew J
MJ
Olszta
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Ravi K
RK
Kukkadapu
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Lyle M
0000-0001-8335-0126
LM
Gordon
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Manjula I
MI
Nandasiri
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Greg
G
Whyatt
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Chris
C
Clayton
Energy &Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
David W
DW
Gotthold
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Mark H
MH
Engelhard
Fundamental and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Herbert T
HT
Schaef