Porous PVdF/GO nanofibrous membranes for selective separation and recycling of charged organic dyes from water

Abdul Ghaffar, Zhejiang University, Hangzhou, China

Graphene oxide (GO) membranes are robust and continue to attract great attention due to their fascinating properties, despite their potential issues regarding stability because of negatively charged functional groups and selectivity in aqueous-phase processing. That being said, however, the functional groups of GO could be used for membrane surface modification, while ensuring simultaneous removal and recycling of industrial organic dyes. A versatile porous structured polyvinylidene fluoride−graphene oxide (PVdF-GO) nanofibrous membranes (NFMs), was prepared by electrospinning approach for selective separation and filtration. The GO nanosheets were distributed homogeneously throughout the PVdF nanofiber, regulating the surface morphology and performance of PVdF-GO NFM. The PVdF-GO NFMs exhibit high mechanical strength and surface free energy (SFE), consequently resulting high permeation and filtration efficiency as compared to PVdF NFM. The selectivity (99%) toward positively charged dyes based on electrostatic attraction, while maintaining rejection (100%) for negatively charged dye from mixed solutions highlight the role of GO in PVdF-GO NFM, owing to uniform pores and negatively charged surface. In addition, the actual efficiency of NFMs could be recovered easily up to three consecutive filtration cycles by regeneration, thereby assuring high stability. The high permeation, purification and filtration efficiency, good stability and recycling of PVdF-GO NFMs are promising for use in practical water purification and applications, particularly for selective filtration and recycling of dyes.

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