Layer-by-Layer Assembly of Graphene Oxide Nanosheets on Polyamide Membranes for Durable Reverse-Osmosis Applications

Abstract

Improving membrane durability associated with fouling and chlorine resistance remains one of the major challenges in desalination membrane technology. Here, we demonstrate that attractive features of graphene oxide (GO) nanosheets such as high hydrophilicity, chemical robustness, and ultrafast water permeation can be harnessed for a dual-action barrier coating layer that enhances resistance to both fouling and chlorine-induced degradation of polyamide (PA) thin-film composite (TFC) membranes while preserving their separation performance. GO multilayers were coated on the PA-TFC membrane surfaces via layer-by-layer (LbL) deposition of oppositely charged GO nanosheets. Consequently, it was shown that the conformal GO coating layer can increase the surface hydrophilicity and reduce the surface roughness, leading to the significantly improved antifouling performance against a protein foulant. It was also demonstrated that the chemically inert nature of GO nanosheets enables the GO coating layer to act as a chlorine barrier for the underlying PA membrane, resulting in a profound suppression of the membrane degradation in salt rejection upon chlorine exposure.

Thin-film composite forward osmosis membranes functionalized with graphene oxide–silver nanocomposites for biofouling control

“…transport properties [16,41]. Similar observations have also been reported for TFC RO 476 membranes modified with multiple layers of GO sheets [42]. This low impact of GO on the 477 membrane performance is probably due to its atomic thickness and hydrophilic nature.…”

Shielding membrane surface carboxyl groups by covalent-binding graphene oxide to improve anti-fouling property and the simultaneous promotion of flux

“…Previous studies also found that after surface modification by GO, the membrane anti-fouling properties to the protein, alginate or humic acid foulants were obviously improved Choi et al, 2013;Hu et al, 2016;Han et al, 2015). And the improvement of fouling resistance was attributed to hydrophilicity increase and surface roughness reducing Choi et al, 2013;Hu et al, 2016;Han et al, 2015). Even though GO have demonstrated effective adsorption performance , it was explained that the organic foulants were adsorbed mainly on the basal plane of GO nanosheets while water enters in the GO modified membrane surface primarily around the oxidized edges of GO nanosheets (Hu et al, 2016).…”

“…Membrane fouling testing was performed in the same modified SEPA CF II membrane cell system mentioned in Section 2.4 using a previously reported process (Mo et al, 2012;Choi et al, 2013;Han et al, 2015). The Ca 2þ /organic foulants compound synthetic wastewater was constituted by CaCl 2 , NaCl, NaHCO 3 and sodium alginate (Mo et al, 2012;Lu et al, 2013).…”

“…Several membrane surface modification reports have been published that use GO to improve flux (Chae et al, 2015;Berean et al, 2015), increase antibiofouling properties Perreault et al, 2014;Zou et al, 2016) and enhance chlorine resistance properties (Choi et al, 2013). Previous studies also found that after surface modification by GO, the membrane anti-fouling properties to the protein, alginate or humic acid foulants were obviously improved Choi et al, 2013;Hu et al, 2016;Han et al, 2015). And the improvement of fouling resistance was attributed to hydrophilicity increase and surface roughness reducing Choi et al, 2013;Hu et al, 2016;Han et al, 2015).…”

Graphene-Paper Based Electrochemical Sensors

“…Self-assembly is a popular approach towards cost-effective preparation of thin films, which has also been applied for fabricating multilayer graphene papers with tunable composition and architecture [8,10,38]. The driving forces involved in layer-by-layer (LBL) assembly generally include hydrogen bonding, electrostatic interaction and covalent bonding [8,39,40].…”