A robust metal-organic framework nanofibrous membrane as filter for fast separation of cationic dyes from aqueous solution

Abstract

• Bio-MOF-1@TPU NFM with robust mechanical properties was successfully fabricated. • Bio-MOF-1@TPU NFM can be used as a filter to separate cationic dye from aqueous solution. • Bio-MOF-1@TPU NFM exhibited fast filtration ability and stable reuse effect. • The separation process was based on the ion-exchange and monolayer adsorption mechanisms. A robust metal-organic framework (MOF) nanofibrous membrane (NFM) was successfully fabricated via electrospinning by employing thermoplastic polyurethane (TPU) as substrate and encapsulating anionic bio-MOF-1 into TPU nanofibers. Characterization with FT-IR, EDS and PXRD confirmed that the crystal structure of bio-MOF-1 maintained well in TPU nanofibers. Based on the ion-exchange mechanism, the as-prepared bio-MOF-1@TPU NFM can be used as a filter for efficient separation of cationic dyes from mixed dyes aqueous solution. Benefiting from the robust mechanical properties of TPU, the bio-MOF-1@TPU NFM can repeatedly withstand the suction filtration pressure without damage, resulting in a very fast dye separation process that completed within 70 s, and a very stable reuse effect that the removal efficiency of MB + was just 9.0 % less than that of the first filtration after five cycles of use. This work will be useful for the design of MOFs NFMs based on electrospinning applied to fast separating organic dyes from practical wastewater.