High performance graphene oxide nanofiltration membrane prepared by electrospraying for wastewater purification

A high performance graphene oxide nanofiltration membrane (GO NFM) was prepared using the electrospraying technique instead of the traditional vacuum filtration method, which is a facial and scalable method to prepare GO NFMs with diameter of 100 mm. The permeate performance of this novel nanofiltration membrane was evaluated using a dead end filtration device, which gave us a high flux value for pure water (11.13–20.23 L m⁻² h⁻¹ bar⁻¹) even under an extremely low external pressure (1.0 bar). The GO(120) NFM demonstrated high organic dyes rejection rate (98.88%, 98.97%, 100%, and 99.99%, for BF, MB, MO, and EB, respectively). The rejection mechanism for charged dyes was discussed and the results revealed that physical size sieving and electrostatic interaction dominated the rejection mechanism. The rejections rate of GO NFMs for the Na₂SO₄, NaCl, MgSO₄, and MgCl₂ were 63.13%, 27.86%, 41.82%, and 15.00%, respectively, based on the mechanism of Donnan exclusion theory and steric hindrance effect. Furthermore, the GO NFM shows high flux recovery ratio (FRR) values (89.58% and 95.54% for SA and HA), suggesting that the GO NFM is easier to be recovered by DI water washing due to the smooth and hydrophilic surface.