Construction of skyloft-like polyamide membrane on tubular ceramic support for high-flux nanofiltration

Polyamide (PA) thin-film composite membrane has been widely used in water/wastewater treatment, but construction of such membrane on a three-dimensional inorganic macroporous support remains a challenge, thus limiting the further application under harsh conditions. Herein, we propose a skyloft-like PA membrane on a commercial tubular ceramic macrofiltration support. This membrane built on stilts comprises an ultrathin PA canopy of ∼ 33 nm and pillars (∼1 μm-thick) of vertically aligned CoAl-layered double hydroxide (LDH) nanosheets and covalent organic framework (COF) nanospheres. The prepared PA/OH-COF/F-COF/LDH membrane shows a high water permeance of up to 736.6 L m-2h−1 MPa−1 together with a satisfactory rejection rate of > 90 % for various small molecules including dyes and antibiotics (> ∼1 nm). The resultant membrane also demonstrates a good dye desalination performance (with a selectivity of up to 197), illustrating an outstanding permselectivty. A long-term and continuous cross-flow nanofiltration indicates a robust stability of the membrane.