Improved desalination performance of fluorinated graphene oxide blended PVDF electrospun nanofiber membrane for air gap membrane distillation

The high-performance hydrophobic membranes are crucial for the practical application of membrane distillation (MD). The fluorination treatment or inorganic particle incorporation has been widely applied for improving the hydrophobicity of membrane surface. However, the economic and facile method for the fabrication of hydrophobic membranes is still urgently needed. In this study, the fluorinated graphene oxide (FGO) nanosheets were synthesized and used as hydrophobic additives for the polyvinylidenefluoride (PVDF) electrospun nanofiber membrane. The membrane hydrophobicity was greatly improved after the addition of FGO nanosheets due to their inherent strong hydrophobicity and the induced formation of finer nanofibers. In comparison to the control membrane (pristine PVDF membrane), the water flux of the proposed composite membrane with superior salt rejection efficiency of 99.9% was increased by 41.5% (22.2 L/m2.h) when treating 3.5 wt% NaCl solution at the temperature difference of 40 degrees C. The excellent stability of the prepared membrane was verified by a 120-h continuous AGMD operation. The findings from this study demonstrates the FGO nanosheets could be considered as promising materials for the fabrication of high-performance AGMD membranes to promote the application of large-scale AGMD in the desalination and water treatment.