Oily  wastewater and oil spills not only cause large amounts of resource wastefulness,  but

threaten water safety and human health. Besides, for some oily emulsions, the oil droplets

are usually  valuable, such as the soybean oil droplets formed during oil manufacture,  and

the  oil  droplets  carrying  high  valued  product  from  the  extraction  process  or  microemulsion reactor. Therefore, the collection and recovery of oil from water are particularly important.  However, the recovery of oil droplets form emulsions and collection-lossless 

transportation  of  oil  spills  are  still  a  big  challenge,  which  cannot  be  solved  by  current

oil/water separation methods, including the super-wetting strategy. Herein, we designed

and prepared oil-unidirectional Janus membrane via unilateral decoration of commercial

hydrophobic  composite  microfiltration  membranes.  The  obtained  Janus  membrane  is

composed  of  a  thin  hydrophilic  layer  and  thick  hydrophobic  supporting  layer,  and  the

asymmetric surface wettability  can realize the unidirectional oil-transport property, viz.

oil  “diode”.  Therefore,  the  obtained  JMs  with  oil  unidirectional  transport  property  can

realize  the  efficient  collection  and  recovery  of  various  oils.  For  example,  the  J M  can

effectively draw the micrometer-sized oil droplets from various oil-in-water emulsions,

and realize the  collection-lossless transportation  of the oil spills.  Our strategy can firmly

stimulate  and  accelerate  the  advances  of  functional  membranes  toward  the  broad

intelligent and sustainable usages.