Improvement of water filtration performance of graphene oxide membranes on Nylon support by UV-assisted reduction treatment: Control of molecular weight cut-off

Graphene oxide (GO) membranes on Nylon support were modified by UV-assisted reduction to control their behavior in the filtration of water containing organic pollutants. Pyridine, phenol, 2-naphthol and disperse blue 3 were used as probe pollutants to determinate the molecular weight cut-off (MWCO) of the membranes prepared. The membranes were prepared with GO loads of 0.04 and 0.06 mg cm-2 and subjected to UV radiation from a Hg lamp (30 W m-2) for 30-60 min. The non-irradiated membranes showed MWCO ca. 300 Da, with rejection values above 90 % for disperse blue 3, while rejection for 2-naphtol reached 64 %. Irradiation resulted in substantial removal of oxygen surface groups, leading to staking of GO sheets and a decrease of interlayer space. These structural changes narrowed the size of pores thus reducing solutes passage. Rejection of 2-naphtol reached 83 %, i.e. decreasing MWCO to ca. 150 Da. The increase in the rejection of solutes was higher for membranes with a GO load of 0.06 mg cm-2, however similar water permeability was achieved regardless the GO load. UV-reduction shows a high potential for controlling the rejection of solutes by GO membranes on Nylon support while maintaining good permeability.

Automated summary

This study modified graphene oxide (GO) membranes on Nylon support through UV-assisted reduction to control their behavior in filtering water containing organic pollutants. The irradiation process led to structural changes of the membranes, resulting in smaller pores and increased rejection of solutes while maintaining good water permeability.