Facile preparation of grass-like hierarchical structured γ-AlOOH coated stainless steel mesh with superhydrophobic and superoleophilic for highly efficient oil-water separation

A superhydrophobic and superoleophilic γ-AlOOH membrane on stainless steel mesh was fabricated by an inexpensive, template-free hydrothermal method using Al(NO3)3·9H2O and Na2C2O4 as starting materials. A novel γ-AlOOH film with a grass-like structure was synthesized and grass-like grains were tightly connected to form a hierarchical microstructure, which created a rougher stainless steel mesh surface. The influences of the additive amount of Na2C2O4 and Al(NO3)3·9H2O on morphology and water contact angle of products were discussed. The prepared film is superhydrophobic not only for pure water but also for corrosive water under acidic or alkaline conditions. The obtained superhydrophobic and superlipophilic coated mesh exhibited high efficient oil/water separation. Besides the maximum diesel-water separation efficiency reach 99.6%, a high water intrusion pressure value of 2.2 kPa is also calculated, which make it promising application in large-scale, high-efficient and reusable oil/water separation filed.