Dehydration of acetic acid using layered graphene oxide (GO) membrane through forward osmosis (FO) process: a molecular dynamics study

Abstract

ABSTRACT The applicability of layered graphene oxide (GO) membrane for dehydration of acetic acid using forward osmosis (FO) process is investigated with non-equilibrium molecular dynamics (MD) simulations. The performance of layered GO membrane with different pore offset distance (W) and interlayer distance (H) is investigated. The parameter W is a measure of the size of the constituting GO nanosheets. With the increase in W, the water permeance through layered GO membrane decreases and salt rejection increases. On the other hand, as H increases from 8 Å to 12 Å, the water permeance of the layered GO membrane increases and the corresponding salt rejection decreases. But as H increases beyond 12 Å, the water permeance through layered GO membrane decreases and salt rejection increases. The presence of pinhole defects on the GO nanosheets of layered GO membrane provides shorter route to the water molecules for trans-sheet flow which increases the water permeance of the membranes. With the increase in draw solution concentration the water permeance through the membrane increases but the corresponding variation in the draw solute rejection is much less (<2.0%). With the appropriate tuning of sizes of the GO nanosheets and interlayer spacings, layered GO membrane could be a suitable candidate for dehydration of acetic acid using FO process.