Growing nearly vertically aligned ZnO nanorod arrays on porous α-Al2O3 membranes to enhance the separation of MTBE from aqueous solution

•Nearly vertically aligned ZnO nanorod arrays are formed on the α-Al2O3 membranes.•The load of fluorocarbon groups has been raised.•A superhydrophobic surface with a water angle of 155° has been obtained.•The MTBE/water separation factor has been dramatically enhanced to 55.7 from 7.7.•The MTBE concentration has been significantly concentrated to 72.9 wt%.