| How to effectively clean up oil spills and oily wastewate are important for protecting ecological environment.Materials with special wettability,such as superhydrophobicity-superoleophilicity,superhydrophilicity-superoleophobicity and special wettable materials with irritating responsiveness,due to these materials show special wettability to water and oil,this kind of material has become an effective method for dealing with marine oil spills and industrial oily wastewater.In addition,these materials also can be used in anti-corrosion,antibacterial,drag reduction,anti-icing,self-cleaning and so on.The wettability of the material is controlled by the micro-roughness of the surface and the chemical composition.Therefore,it is crucial to change the microstructure and surface chemical composition of the material using a simple method for fabricating special wettability material.304 stainless steel meshes were selected as substrate,which has a relatively stable metal skeleton structure,hence,stainless steel meshes which have special wettability can be obtained by a simple surface modification method.We studied the surface wettability before and after modification and the relation between special wettability and chemical composition.In addition,the application of the hydrophobically modified stainless steel mesh was investigated.The main works are summarized as follows:1.304 stainless steel mesh membrane was selected as substrate,and the hydrophobic agent was prepared by vinyl triethoxysilane(VTMO)and fumed silica(TS720).The superhydrophobic mesh material was prepared by dip-coating method.The surface composition of stainless steel mesh was analyzed by FTIR-ATR and EDS to discuss the mechanism of such special wettability.In addition,the separation ability,recyclability and chemical stability of the superhydrophobicity-superoleophilicity meshes material were investigated.The results show that the separation efficiency of the modified mesh film for the mixture of water and oils with different viscosities is more than 90%.After 55 cycles of separation experiments,the separation efficiency could still remain to 92.5%.The contactangle measurement of the modified mesh was carried out.According to the test results,the water droplets contact angle of the modified mesh can reach 152±0.8°.2.An appropriate roughness was prepared on the mesh surface by chemical etching of HF(40wt%),and then the superhydrophobicity-superoleophilicity mesh material was fabricated after modification with 12-hydroxystearic acid(12-HSA).We studied the influence of chemical etching time in HF and selecting different solvents for12-hydroxystearic acid solution on the wettability of the hydrophobically modified mesh.Besides,we also investigated oil/water separation ability,recyclability and chemical stability of modified mesh material.Meanwhile,a multi-stage parallel oil/water separation device was designed for the cyclic separation of oil/water mixture by using the modified superhydrophobic mesh material.The results show that different solvents can affect the wettability of the hydrophobically modified mesh.This superhydrophobic mesh material has high separation efficiency for oil/water mixture and show excellent recyclability.When separating the mixture of petroleum ether and water,the separation efficiency is the highest,reaching 95.65%,and the separation efficiency of other oils is also above 92%.According to the measurement of the contact angle,the water contact angle of the modified stainless steel mesh can reach 151±0.8°,and the oil droplets spread rapidly on the surface and the contact angle of oil is 0°.3.The 304 stainless steel mesh was selected as substrate.The wettability of original stainless steel mesh was transformed into superhydrophobicity-superoleophilicity after chemical etching in HF and self-assembly reaction in octadecanethiol solution.Using SPSS software to design orthogonal experiment to explore the optimum experiment condition.In order to explore the influence of differenrt experiment factor to the wettability of modified mesh,self-assembly reaction time,the concentration of octadecanethiol solution and the chemical etching time in HF solution were studied.The water contact angle of the modified stainless steel mesh was measured to be 152.5°,and the contact angle of oil was 0°.In addition,the adhesion of hydrophobic coating on the modified mesh and oil/water separation ability of modified mesh were also tested.,meanwhile,the mechanism of forming superhydrophobic coating on the modified mesh surface was discussed.The results show that this modified mesh material show high separation ability for oil/water mixture and the rational use of SPSS software can effectively optimize the experimental conditions. |
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