Membrane filtration is a promising technology in the applications of water and wastewater treatments. Graphene oxide (GO) is a two-dimensional carbon material that has many oxygenated groups including hydroxyl, epoxy, carbonyl, and carboxyl groups on the basal planes and edges. It typically has a hydrophilic nature and moderate specific surface area by retaining the layer structure of graphene. Nano-scale pores in a lattice and interlayer space of GO provide an opportunity for its potential membrane applications such as rejection of pollutants in aqueous solutions. In this study, a GO-Fe membrane was fabricated by adding Fe2+ during vacuum-assisted preparation of a GO membrane. The GO-Fe membrane was fabricated successfully possibly due to the binding between Fe and GO. More importantly, while catalytic oxidation of organic pollutants by the reaction between GO-Fe particles and H2O2 has been observed in our previous studies, the objective of this study was to investigate the impacts of filtration with different solutions including oxidant (H2O2, pH 4.5), acid (H2SO4, pH 3.0), base (NaOH, pH 9.7), and water (pH 7.0) on the surface characteristics and permeation performances of this GO-Fe membrane. In the results of the lab-scale experiments, the maximum and minimum permeate fluxes were found in the experiments using water and acid, respectively. The O-H component of the membrane was increased by hydration during water filtration, elevating the permeation flux by increasing the interlayer distance that oppositely affected the pollutant rejection efficiency. Acid filtration increased the Fe concentration in the permeate, suggesting the surface damage in this experiment. The oxidant and base filtration enhanced the oxygenation and protonation of the membrane, respectively, and both resulted in moderate permeate fluxes. The results of this study were compared with others that reported the permeation fluxes of different GO-based membranes and their removal efficiencies of various organic pollutants. The findings of this study provided interesting discussions on the influence on a GO membrane modified by a divalent cation when the membrane was used under different filtration scenarios such as at different pHs or in the presence of a strong oxidant such as H2O2.

Effects of filtration with water, acid, base, or oxidant on a graphene oxide-iron membrane: Changes of surface characteristic and permeate flux

ACS Spring Meeting 2021

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