Fabrication of superhydrophobic cotton fabric treated with n-dodecyltrimethoxysilane/zirconium oxychloride for highly efficient oil/water separation

A simple sol–gel method was proposed to fabricate superhydrophobic cotton fabric (S-fabric) with a water contact angle of 155.6°. A co-condensation process between zirconium hydroxide (Zr(OH)₄) and n-dodecyltrimethoxysilane under alkaline condition was presented. The functionalized Zr(OH)₄ NPs with long-chain alkyl groups (–(CH₂)₁₁CH₃) offered both hierarchical roughness and lower surface energy for S-fabric. The functional groups, surface morphology, element distribution, and surface roughness changes were examined by FTIR, SEM, EDS, and 3D optical profiler, respectively. And the results indicated that the cotton fabric was successfully modified. The obtained cotton fabric retained chemical stability after 72 h immersion in different extreme conditions, and mechanical durability after 200 cm of abrasion length. The S-fabric could be applied in the separation of oil–water mixture (n-hexane, n-heptane, n-dodecane, cyclohexane and kerosene) with the high efficiency (> 96%), and the efficiency remained stable after 50 separation cycles (n-dodecane and n-hexane). The facile preparation, chemical and mechanical stability, high separation efficiency, and good reusability of S-fabric indicated the potential practical application value in oil/water separation.