A low-pressure GO nanofiltration membrane crosslinked via ethylenediamine

Laminate graphene oxide (GO) membranes have received increasing attention recently in the water processing field due to their unique properties. However, the hydration of hydrophilic graphene oxide nanosheets leads to instability of GO membranes in aqueous solutions. In this study, ethylenediamine (EDA) was employed to crosslink GO nanosheets in a GO membrane supported on a brominated polyphenylene oxide (BPPO). In addition, because the O˭C-OH group of GO reacted with the amine group of EDA, the GO layer was firmly bonded to the BPPO substrate, as evidenced by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). EDA crosslinking dramatically improved the stability of the GO membranes. After immersion in water for one month, the prepared BPPO/EDA/GO membranes still retained their flux rates and salt rejection capabilities. The water flux rates and salt rejection capabilities of BPPO/EDA/GO membranes can be tuned by controlling GO loading. At a GO loading of 65 mg/m², the BPPO/EDA/GO membrane achieved a relatively high water flux rate of 4.1 L/m² h under a very low transmembrane pressure of 1 bar. Additionally, the salt rejection percentages of Na₂SO₄, MgSO₄ and NaCl were 56.2%, 48% and 36.3%, respectively. Moreover, the BPPO/EDA/GO membrane displayed good antifouling and antibacterial properties.