Abstract:
Forward osmosis (FO) desalination system as a sustainable alternative source of freshwater has been highlighted to improve the energy efficiency of current reverse osmosis (RO) desalination technology. Although the core of FO process is a semipermeable membrane capable of selectively separating pure water from salt water, there are still limitations which diminish process performance. Despite the improvements in thin film composite (TFC) desalination membranes in the past few decades, it is attributed to the trade-off between water flux and salt rejection due to the asymmetric structure and the surface properties of polymeric TFC membranes. To improve these undesired limitations, the mixed matrix membranes (MMMs) which use nanomaterials as a filler material embedded within a polymeric matrix [Lind, et al., ES&T, 2010], that is thin film nanocomposite (TFN) membranes, have been developed that incorporate metal nanoparticles, zeolite, carbon nanotubes, TiO2, graphene and aquaporin etc. In addition, the new classes of inorganic TFN membranes using nanomaterials but not mixed with polymer [Yang, et al., Carbon, 117, 2017;  J.H. Song, et al., RSC Adv., 7, 2017] have been recently proposed towards fabricating highly selective membranes of water molecules.
The objective of this seminar is to present a recent progress on a graphene oxide (GO) nanocomposite membrane with high performance of water selective permeability and high stability in aqueous solution. The graphene could act as a high-permeability membrane, which could reject salt ions with a water permeability 2−3 orders of magnitude higher (ranged from 39 to 66 L per cm2·day·MPa) than commercial RO membrane [Tanugi and Grossman, Nano Lett., 12, 2012]. For advances in fabrication of inorganic TFN membranes, layer-by-layer (LBL) dipping technique was utilized to control the desirable structure, alignment, and chemical functionality that can lead to ultrahigh-permeability membranes. In this study, the laminated GO nanocomposite membrane was fabricated by transfer of GO nanosheets and lamination of GO layers on a substrate membrane and linked the GO layers with chemical linkers to make them stable framework. Then, all the required characterizations and filtration performances are evaluated for GO nanocomposite membrane.