An Adsorptive Membrane Based on Electrospun Graphene Oxide/Poly(vinylidene) Fluoride Fiber Coated with Chitosan for Removal of Manganese Ions from Aqueous Solutions Using a Simple Filtration Process

The goal of this study was to develop an adsorptive membrane based on electrospun graphene oxide/poly(vinylidene) fluoride fiber mat coated with chitosan (GO-PVDF/CS composite membrane) which can potentially be used to remove Mn2+ from aqueous solutions by a continuous filtration process. This composite membrane was composed of two layers: the first layer was the electrospun PVDF fiber mat containing GO, supporting mechanical strength, improving hydrophilicity, and providing adsorptive sites; the second layer was a thin CS film coated on top of the first layer with the aim of significantly enhancing hydrophilicity and adsorption capacity of the composite membrane. The hydrophilicity and porosity of the GO-PVDF/CS composite membrane depended on the concentration of the CS solution, subsequently affecting the Mn2+ removal efficiency of the membrane. The GO-PVDF/CS membrane achieved the maximum Mn2+ removal efficiency of 90.7 wt% by a continuous flow filtration process with a flux of 157.3 L.m(-2).h(-1).bar(-1). The GO-PVDF/CS membrane was able to decrease the concentration of Mn2+ from 5.72 to 0.38 mg/L in the groundwater-contaminated Mn2+ after two filtration processes, reaching the notification level of Mn2+ for drinking water that was allowed by several countries. Therefore, the GO-PVDF/CS membrane can be an effective adsorptive filtration membrane used to remove Mn2+ from groundwater.