y gamma-Al2O3/alpha-Al2O3 hollow fiber nanofiltration (NF) composite membranes with different molecular weight cut-offs (MWC0s) ranging from 1.4 kDa to 14.5 kDa were prepared by dip-coating gamma-AIOOH sol on the ceramic membrane with a mean pore size of 229 nm. The effect of the preparation conditions including soaking time and coating times were investigated by scanning electron microscopy (SEM), dynamic contact angle and membrane performance. The optimal inorganic NF membrane demonstrated a high pure water permeance with high retentions of multivalent ions and low retentions of monovalent ions. The gamma-Al2O3/alpha-Al2O3 inorganic hollow fiber NF membrane shows excellent solvent resistance and good stability. (C) 2015 Elsevier B.V. All rights reserved.