Honeycomb-like polysulphone/polyurethane nanofiber filter for the removal of organic/inorganic species from air streams.

Nanofiber nonwoven filters, especially those prepared by electrospinning, are of particular interest because of their high filtration efficiency. However, existing electrospun filters suffer from inherent limitations in that both strengths and filtration resistances of the filters leave much to be desired. Herein, we present a novel nonwoven filter that is composed of polysulphone and polyurethane nanofibers. By mimicking the honeycomb structure, a heterogeneous distribution of both fiber diameter and fiber density has been achieved. Compared with nanofiber nonwovens with plain architectures, the honeycomb-like nonwovens possess higher filtration efficiency (∼99.939%), better mechanical strength (∼105.24 N g-1) and improved quality factor (∼0.04 Pa-1). The filtration efficiency against both inorganic and organic aerosols is guaranteed through the nanofiber surface geometry and the intrinsic charge-retention capacity of polysulphone. Since the production of this nanofiber filter does not need multistep procedures and can be easily scaled up on a needleless electrospinning device, we anticipate that the strategy of endowing nanofibers with honeycomb texture and charge-retention capacity may lead to the development of advanced fiber filters.