Covalent layer-by-layer grafting (LBLG) functionalized superhydrophobic stainless steel mesh for oil/water separation

• DOI: 10.1016/j.apsusc.2017.02.102
• Publication Date: 2017-02-17T12:16:01Z
• Authors: Bin Jiang; Hongjie Zhang; Yongli Sun; Luhong Zhang; Lidong Xu; Li Hao; Huawei Yang
• Keywords: Triethoxysilane; Surface Modification

Abstract A superhydrophobic and superoleophilic stainless steel (SS) mesh for oil/water separation has been developed by using a novel, facile and inexpensive covalent layer-by-layer grafting (LBLG) method. Hierarchical micro/nanostructure surface was formed through grafting the (3-aminopropyl) triethoxysilane (SCA), polyethylenimine (PEI) and trimesoyl chloride (TMC) onto the mesh in sequence, accompanied with SiO2 nanoparticles subtly and firmly anchored in multilayers. Superhydrophobic characteristic was realized by self-assembly grafting of hydrophobic groups onto the surface. The as-prepared mesh exhibits excellent superhydrophobicity with a water contact angle of 159°. Moreover, with a low sliding angle of 4°, it shows the “lotus effect” for self-cleaning. As for application evaluation, the as-prepared mesh can be used for large-scale separation of oil/water mixtures with a relatively high separation efficiency after 30 times reuse (99.88% for n-octane/water mixture) and a high intrusion pressure (3.58 kPa). More importantly, the mesh exhibited excellent stability in the case of vibration situation, long-term storage as well as saline corrosion conditions, and the compatible pH range was determined to be 1–13. In summary, this work provides a brand new method of modifying SS mesh in a covalent LBLG way, and makes it possible to introduce various functionalized groups onto the surface.