Attapulgite-based nanofiber membrane with oriented channels for high-efficiency oil-water separation

Nanofiber membranes are distinguished for their high porosity and interconnected pore structures . However, their separation application and performances are affected by irregular pore structures which are formed by the randomly packing of nanofibers. Herein, we report a facile approach to produce nanofiber membranes with oriented channels, narrow pore size, and low tortuosity. The membranes show a bi-layered structure where magnetic attapulgite (mATP) nanofiber layers are directly supported on macroporous Al 2 O 3 substrates. The mATP layers are prepared by drop-coating suspensions on top of the substrates pre-filled with water, and the ordered pore structures are formed at the presence of a magnetic field. Compared with the unordered membranes, average pore size of the ordered membranes reduces from 0.45 to 0.28 μm, with the water permeance increase from 1007 to 1121 L m −2  h −1 ·bar −1 . Moreover, the stationary flux of ordered membranes increase by 59% with the retention to oil-in-water emulsion increase from 98.7% to 99.2%. Analysis of membrane fouling using the Hermia model shows that the ordered membrane can reduce membrane blocking and thus facilitate membrane cleaning and restore of separation performance.