Highly permeable Al2O3 microfiltration membranes with holey interior structure achieved through sacrificial C particles

Alumina (Al2O3) microfiltration membranes with holey interior structure exhibit the combined desirable properties of both superior permeability and good retention performance. These membranes are purposely made to consist of a holey intermediate layer with a thickness in the range 12.9-15.5 mu m and a top filtration layer of very thin thickness in the range 1.8-2.8 mu m, fabricated by cosintering with sacrificial carbon (C) particles. The holey structure in the intermediate layer, which can be well controlled by regulating the amount of C particles added to Al2O3 particles, contains plenty of holes of 1-5 mu m in size, thereby possessing much reduced water flow resistance. The thin top filtration layer, which contains uniformly distributed nanopores of 90-100 nm in size, functions as the selective layer, thereby ensuring a good retention performance. At the C particle content of 30 wt. %, the Al2O3 membrane with holey interior structure demonstrates a super-high pure water flux (3358 Lm(-2)h(-1)), which is almost twice that of the membrane without holey interior structure (1697 Lm(-2)h(-1)), while the mechanical strength and retention performance are well maintained.