Preparation Of Superhydrophobic Surface Based On Halloysite Nanotubes For Oil/Water Separation

Superhydrophobic surface plays an important role in handing oil spill accidents.However,its practical application is often limited by the preparation process and the cost of the raw materials.Therefore,it is very important to explor new preparation processes and develop new superhydrophobic materials.In this study,a preliminary exploration of constructing the processes of superhydrophobic surfaces based on halloysite nanotubes?HNTs?was conducted and the conditions were optimized.The details are as follows:?1?An increasing attention has been paid to the low-cost and environmentally friendly route for oil/water separation.However,the development of the superhydrophobic surface is still hindered by tedious multi-step preparation procedure and the high-cost manufacture.In this paper,the HNTs were modified by octadecyl trimethoxysilane?ODTMS?first and then loaded on the cotton surface by a simple dipping process.The superhydrophobic cotton was obtained with static water contact angle?WCA?of 164^o which can be used for oil/water separation.The introduce of modified HNTs onto the cotton surface decreases the surface energy and increases roughness simultaneously,resulting in a superhydrophobic and superoleophilic surface.The prepared cotton shows a high separation efficiency up to 99.99%,and maintains its good performance in at least 10 separation cycles.It can absorb oils over 12.5 times of its own weight.In addition,the fabricated superhydrophobic cotton still retains good hydrophobicity under more demanding circumstances.?2?Building superhydrophobic surface via the interfacial polymerization?IP?methodology remains seldom unstudied.In this paper,HNTs were fixed on melamine sponge?MS sponge?surface by IP occured between 1,3,5-benzenetricarbonyl trichloride?TMC??oil monomer?and polyethylenimine?PEI??aqueous monomer?forming polyamide film?PAF?,then the superhydrophobic sponge was obtained by imparting hydrophobic Si O₂ as a low-surface-energy initiator on PAF wrapped on MS sponge.The as-prepared superhydrophobic sponge?denoted as MS-PAF-HNTs/Si O₂ sponge?has a well-preserved interconnected structure equal to the pristine MS sponge and a bulk superhydrophobicity with a WCA of 158^o.It is noteworthy that the MS-PAF-HNTs/Si O₂ sponge has an exceptional oil/water separation performance with a separation efficiency more than 99.91%of all oil/water mixtures in this experiment.In addition,the ultrasonic experiment also proves that the superhydrophobic coating has good stability.More importantly,continuous separation of oil/water separation can be achieved by combining the MS-PAF-HNTs/Si O₂ sponge with vacuum system.