Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application

Abstract

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

Graphene Oxide-Based Membranes Intercalated with an Aromatic Crosslinker for Low-Pressure Nanofiltration

“…Overall, we confirmed that DCX crosslinking can contribute to improving the salt-rejection efficiencies of GO membranes. To further evaluate the effect of DCX crosslinking, we also compared the NF performance of our DCX/GO membranes by benchmarking the Na 2 SO 4 rejection and the PWP performances of previously reported crosslinked GO membranes ( Figure 10 and Table S3 ) [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. The results revealed that our GO/DCX membranes outperformed other crosslinked GO membranes.…”

“… Performance comparison plot showing the Na2SO4 rejection efficiencies and the PWP of GO-based NF membranes, including our GO membranes [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. …”

“…Figure S1: Color change of the prepared membranes from dark blonde to dark brown; Figure S2: The pure water flux versus pressure (1−5 bar) of the prepared membranes; Table S1: Dye rejection efficiencies and PWP of the GO membranes at 1 bar; Table S2: Salt rejection efficiencies of the GO membranes under two different applied pressures; Table S3: Performance comparison of crosslinked GO-based NF membranes for water purification. References [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ] are cited in the Supplementary Materials.…”

Fabrication and performance analysis of graphene oxide-based composite membrane to separate microplastics from synthetic wastewater

“…A vacuum ltration unit (dead end ltration) was used to analyze the water permeability and MPs rejection capacity of the fabricated membrane. Before permeance testing, all samples were operated for 15 min by using DI feed water to reduce the impact of membrane compaction on membrane activity(Park, Nisola et al 2021). Here the following equation was used to analyze membrane permeability(Du, Huang et al 2020).…”

“…J = V A × t × P 2In this equation, J is representing the permeate ux while V, A, t, and P are highlighting the volume of permeate water, effective surface area of membrane, tine duration, and transmembrane pressure respectively. Regarding the evaluation of MPs rejection capacity, following equation was used during experimentation(Park, Nisola et al 2021).R(%) = 100 × 1 − Cp Cf3In this equation, R is representing the MPs rejection rate while Cp and Cf are the permeate concentration and feed concentration respectively.…”