Pressure-assisted self-assembly technique for fabricating composite membranes consisting of highly ordered selective laminate layers of amphiphilic graphene oxide

Synthesis of graphene oxide membranes and their behavior in water and isopropanol

“…However, a finite amount of GO is required to have a significant rejection for solute (Size > 1.3 nm) depending on the method for synthesis of the GO membranes [16,20]. In our experiments, we used the GO loading of 120 mg/m 2 ; the water permeability of the corresponding 48 nm thick GO membranes had an average value of 3.7 LMH/bar with a standard deviation of 2.4 LMH/bar, which are in the same order of magnitude of GO membranes prepared by the filtering methods [20,33,44]. During the evaporation of thin film of the GO suspension, the “coffee ring” effect lead to the variation in thickness of the deposited GO layer over different parts of the membrane [45,46].…”

“…Hence, this IR study reveals that the isopropanol does not form a stable adsorbates on the GO sheet surface at room temperature. Recent works of Lai group also showed that the inter-layer distance for the isopropanol soaked GO membrane and the dry GO membrane are the same at room temperature indicating no isopropanol adsorption [33]. …”

“…Water can form a stable adsorbates on the GO surface which has been observed to narrow the capillaries for flow of the fluids. This led to improved selectivity of GO membranes for gas phase separations [3,33]. Thermodynamic simulations performed by Korobov et al suggest the different extent of intercalation of various solvent molecules in GO nanochannels [34].…”

Ultrathin graphene oxide nanosheet membranes with various d -spacing assembled using the pressure-assisted filtration method for removing natural organic matter

“…GO membranes can be fabricated from GO nanosheets by using different methods, including filtration assembly [7][8][9][10], layer-by-layer deposition [11][12][13], and spin coating [14,15]. Among these methods, filtration assembly is facile, effective and frequently used in experiments.…”

“…Layer-stacked GO membranes have been wildly used in gas separation, pervaporation dehydration, seawater desalination, organic matter purification and other fields. Several studies have demonstrated that multilayered graphene oxides have excellent selectivity for ethanol, isopropanol or ethyl acetate [7,10] dehydration through pervaporation with high flux. In addition, GO membranes could be used to separate water/alcohol mixtures in the liquid phase [20].…”