Facile fabrication of polyethyleneimine interlayer-assisted graphene oxide incorporated reverse osmosis membranes for water desalination

Current reverse osmosis membrane still suffers from permeability/selectivity trade-off, chlorine attack and fouling. To address these problems, a new interlayer-assisted interfacial polymerization (i.e., polyethyleneimine (PEI) interlayer) in the presence of graphene oxide (GO) at various loading was adopted in this work. Their effects on membrane properties and performances were systematically investigated. Results showed that the PEIinterlayered thin film composite (iTFC) membrane exhibited higher pure water permeance (PWP) (1.76 L/m(2).h.bar) and NaCl rejection (97.69%) compared to the conventional TFC (cTFC) membrane (1.34 L/m(2).h.bar; 96.91%), assigning to the thin and compact PA formed. Performance of iTFC membrane was further enhanced upon inclusion of 0.01 wt/v% GO, producing PEI-interlayered thin film nanocomposite (iTFN-10) membrane with greater PWP (2.66 L/m(2).h.bar) without compensating rejection. This was ascribed to the enhanced surface roughness, hydrophilicity and nanochannels created by GO within the PA. The antifouling property of iTFN-10 membrane was comparable with commercial TFC but better than iTFC membrane. Unlike iTFC membrane, the NaCl rejection of iTFN-10 membrane was least deteriorated after chlorination. This membrane also demonstrated better antibacterial properties (E. coli: 44.26% and S. aureus: 77.55%) than commercial membrane (E. coli: 24.68% and S. aureus: 48.98%) due to the presence of amine groups on membrane surface.

Automated summary

In this study, a novel interlayer-assisted interfacial polymerization technique with the inclusion of graphene oxide (GO) was used to improve the permeability/selectivity trade-off, chlorine attack, and fouling issues of reverse osmosis membranes. The results showed that the PEI-interlayered thin film composite (iTFC) membrane exhibited higher pure water permeance and NaCl rejection compared to the conventional TFC (cTFC) membrane. The inclusion of 0.01 wt/v% GO further enhanced the performance of the iTFC membrane, producing a PEI-interlayered thin film nanocomposite (iTFN-10) membrane with greater pure water permeance without compromising rejection. The iTFN-10 membrane also demonstrated better antifouling and antibacterial properties compared to commercial membranes.