Operando study of water vapor transport through ultra-thin graphene oxide membranes
Abstract
The paper reports operando study of ultra-thin (50 nm) graphene oxide membranes by grazing incidence x-ray scattering in air dehumidification experiments. Absorption of water vapors in GO layers follows a modified Kelvin equation revealing condensation in an elastic slit, while desorption of water is limited by a few outer GO layers providing bottleneck restrictions to water transport and resulting in classical H2-type isotherms. GO interlayer distances (d) vary in range from 7.2 Å to 11.5 Å depending on partial water pressures in a feed stream and permeate. The permeance of water vapor through GO decreases steadily with decreasing interlayer distance between GO sheets from 80 000 l/(m2 · atm · h) to 30 000 l/(m2 · atm · h) falling down to negligible values below d ≈ 9.2 Å. Water transport in GO is described by Poiseuille equation and hopping diffusion depending on the number of water layers between GO planes, and was modelled with semi-empirical methods. It is shown the performance of thin GO membranes is strongly governed by the interstitial water quantity as dictated by water partial pressure.
- Publication:
-
2D Materials
- Pub Date:
- July 2019
- DOI:
- 10.1088/2053-1583/ab15ec
- Bibcode:
- 2019TDM.....6c5039E
- Keywords:
-
- graphene oxide;
- membranes;
- gas dehumidification;
- operando experiment;
- capillary condensation;
- anodic alumina