PEG functionalized graphene oxide-silver nano-additive for enhanced hydrophilicity, permeability and fouling resistance properties of PVDF-co-HFP membranes

In this study, polyethylene glycol (PEG) functionalized graphene oxide-silver nanocomposite (PEG-GOAg) was used as an effective nano-additive to enhance the hydrophilicity, permeability and antifouling resistance of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) support membrane. PEG-GOAg was synthesized by in-situ reduction of GO nanosheets with AgNO3 followed by covalent PEGylation reaction. PEG-GOAg active layer based PVDF-co-HFP membranes were then fabricated by resin infiltration method. Water contact angle of pristine membrane decreased effectively from 115.02° to 38.77° upon PEG-functionalization (1 PEG-GOAg-P). PEG-GOAg loading enhanced the hydrophilicity, permeability, porosity and antifouling properties of pristine membrane by up to 1 wt% due to intercalation of PEG chains on GOAg nanostructure. Water flux capacity of Pristine-P and GOAg-P membranes exhibited lower flux values with 216 and 564 Lm−2 h−1, respectively as compared with that of 1 PEG-GOAg-P membrane, which increased to 906 Lm−2 h−1. The 1 PEG-GOAg-P membrane also showed highest flux recovery ratio (91.3%) and BSA protein rejection rate (95.1%). Further, irreversible fouling ratio was lower with 1 PEG-GOAg-P (Rir ˜8.6%) as compared with pristine (49.1%) and 1 GOAg-P (22.8%) membranes, which demonstrated the high water permeability performance of 1 PEG-GOAg-P membrane. The presented study offers a great potential to optimize quality and cost in fabrication of high-performance polymeric nanocomposite membranes for a wide range of industrial ultrafiltration applications