Preparation Of Superhydrophobic And Superlipophilic Nickel Mesh And Its Oil-Water Separation Performance

The discharge of industrial oily wastewater and oil spill at sea have caused serious water pollution,which has threatened the survival of human and marine organisms.Therefore,in order to deal with oil pollution and protect water resources,advanced oilwater separation technology is needed to separate oil-water mixture.Inspired by the principle of bionics,people try to use the method of preparing special wettable surface to realize oil-water separation.The method has the advantages of high efficiency,environmental protection and simplicity,so it has attracted the attention of researchers.In this paper,the principle of bionics is used to prepare the superhydrophobic and superlipophilic surface on the nickel mesh,so that the nickel mesh can successfully achieve the purpose of oil-water separation,and the prepared superhydrophobic and superlipophilic nickel mesh can be reused for many times.Firstly,the nickel mesh with pore size of 0.05 mm was used as the substrate,the surface was treated by simple hydrothermal method,and the rough structure of zinc oxide was successfully attached to the surface.The surface was modified by hexadecyltrimethoxysilane(HDS)by chemical vapor deposition to prepare superhydrophobic and superlipophilic nickel mesh.The results show that the water contact angle on the nickel mesh surface is up to 143°,and the contact angle with nhexane,n-octane and other oil products is 0°,and the oil-water separation efficiency of HDS modified superhydrophobic nickel mesh for different oils can reach more than 91%,which has good oil-water separation performance.After being reused for 50 times,it still maintains efficient oil-water separation capacity and has good reuse performance.After soaking in strong acid and strong alkali for 24 hours,the oil-water separation efficiency of nickel mesh samples remains above 90%,reflecting the strong acid and alkali corrosion resistance of superhydrophobic and superlipophilic nickel mesh.In order to quantitatively analyze the influence of various factors on superhydrophobic and superlipophilic properties,16 experiments with three factors and four levels were designed by using the method of orthogonal experiment.The analysis shows that the influence degree of various factors on surface wettability is ranked from high to low as carbon chain length of organosilane modified material > reactant concentration > growth time,the best experimental conditions are as follows:octadecyltrimethoxysilane(ODS)(carbon chain length 18)is selected as the organosilane modified material;the reactant concentration is 0.05mol/L;the hydrothermal growth time was 7 h.Finally,the effect of organosilane modified material on the surface wettability of superhydrophobic and superlipophilic nickel mesh was systematically studied.Zn O micro nanostructures were grown by low-temperature hydrothermal method,and a layer of silane monolayer with low surface energy was deposited on the surface to prepare nickel mesh with superhydrophobicity and superlipophilicity.The longer the carbon chain of silane molecules deposited,the stronger the surface wettability of nickel mesh.The maximum contact angle with water can reach 151°(rolling angle is only 3°),and the contact angle with oil is 0°,which has good hydrophobicity and lipophilicity.The nickel mesh modified by different carbon chain length materials can achieve the separation efficiency of more than 85%,and the longer the carbon chain of the modified material,the higher the oil-water separation efficiency.Among them,the superhydrophobic and superlipophilic nickel mesh modified by ODS with the longest carbon chain has a separation efficiency of more than 94% for different oil products such as n-hexane,nheptane and n-octane,which has a strong oil-water separation ability.After the prepared nickel mesh modified with different carbon chain length is reused for 50 times,the separation efficiency of oil-water mixture remains above 88%,and the contact angle with water can still reach more than 130°,maintaining high hydrophobicity,reflecting good reuse performance.