Freestanding bacterial cellulose-graphene oxide composite membranes with high mechanical strength for selective ion permeation.

Qile Fang,Zhi Zheng,Zhaoping Liu,Xufeng Zhou,Wei Deng

doi:10.1038/srep33185

Qile Fang, Zhi Zheng + Show 3 more

Open Access

https://doi.org/10.1038/srep33185

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Abstract

Graphene oxide (GO) based membranes have been widely applied in molecular separation based on the size exclusion effect of the nanochannels formed by stacked GO sheets. However, it’s still a challenge to prepare a freestanding GO-based membrane with high mechanical strength and structural stability which is prerequisite for separation application in aqueous solution. Here, a freestanding composite membrane based on bacterial cellulose (BC) and GO is designed and prepared. BC network provides a porous skeleton to spread GO sheets and uniformly incorporates into the GO layers, which endows the BC + GO composite membrane with well water-stability, excellent tensile strength, as well as improved toughness, guaranteeing its separation applicability in water environment. The resulting BC + GO membrane exhibits obviously discrepant permeation properties for different inorganic/organic ions with different size, and in particular, it can quickly separate ions in nano-scale from angstrom-scale. Therefore, this novel composite membrane is considered to be a promising candidate in the applications of water purification, food industry, biomedicine, and pharmaceutical and fuel separation.

Highlights

IntroductionHow to prepare a free-standing graphene oxide (GO)-based membrane with good structural stability in aqueous environment, good mechanical strength and excellent separation performance for different ions/molecules simultaneously is still a driven goal in this novel separation membrane field
In order to obtain homogenous mixture of Bacterial cellulose (BC) and graphene oxide (GO), we smashed the BC hydrogel into micro-hydrogel with a mincer and freeze-dried it as shown in Supplementary Fig. S1a. It can be seen from the scanning electron microscopy (SEM) image in Supplementary Fig. S1b that the treated BC displays a well network structure constituted of numerous fibers entangling together
We have developed a high-performance separation membrane based on bacterial cellulose and graphene oxide

Summary

Introduction

How to prepare a free-standing GO-based membrane with good structural stability in aqueous environment, good mechanical strength and excellent separation performance for different ions/molecules simultaneously is still a driven goal in this novel separation membrane field. The mixture of commercial BC and GO nanosheets were vacuum filtrated to form a free-standing composite BC +GO membrane (as shown in Fig. 1) in which GO nanosheets spread on porous BC skeleton This novel composite membrane presents well water-stability, excellent tensile strength, as well as improved toughness. Of great importance is that it exhibits obviously discrepant permeation properties for different inorganic/organic ions with different size These properties make the composite membrane a promising candidate in the applications such as water purification These properties make the composite membrane a promising candidate in the applications such as water purification (e. g., decolorization of dye wastewater, bacterial filtration), food industry (e. g., decolorization or concentration of beverage/wine), pharmaceutical and fuel separation (e. g., reagent or protein purification, paraffin separation in crude oil treatment), and biomedicine (e.g., artificial kidneys and dialysis) that require precise separation of large and small molecules/ions[14]

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