Study On Preparation Of Superhydrophobic Copper Mesh For Oil-Water Separation And Its Performance

A large amount of oily wastewater from industrial production and daily life,not only cause unrecoverable pollution and damage to the ecosystem,but also waste a lot of valuable energy.Therefore the effective separation of oily wastewater is imminent.Superwetting materials have solved the problems of low efficiency,high energy consumption and poor selectivity of the traditional separation method.The superhydrophobic-superlipophilic material is more suitable for the separation of large-area oil-w-ater mixture,but the disadvantages are obvious,such as the defects of cumbersome process,use of toxic reagents(such as fluorine),and difficulty in large-scale production.In this research background,a superhydrophobic-superlipophilic copper mesh was prepared by three simple and efficient methods with a 200-mesh copper mesh as the substrate.Applied to oil-water separation in laboratory and its performance is evaluated and compared.The specific contents and results are as follows:(1)Preparation of superhydrophobic copper mesh by in situ growth method.The copper mesh was placed in a mixed solution of sodium thiosulfate and copper chloride to carry out a reaction,and a micro-particle structure was grown in situ on the surface thereof.and a superhydrophobic copper mesh was obtained by modification with 1-dodecanethiol.The preparation conditions are optimized,the contact angle of the copper mesh can reach 154?,and the formation mechanism is explained by analyzing the surface morphology and chemical composition of the copper mesh surface.The copper mesh prepared by the method can withstand the extreme temperature of 150? and has good resistance to the salt solution,and the separation efficiency of the copper mesh for the four oil-water mixtures is above 80%.(2)Preparation of superhydrophobic copper mesh by etching.The nano-needle structure was prepared on the surface of the copper mesh by optimizing the etching conditions.The modification effect of four hydrophobic modifiers:1-dodecanethiol,1-octadecanethiol,stearic acid and lauric acid was studied based on the etched copper mesh.Among them,The modification of 1-octadecanethiol the at a concentration of 10 mM for 5 min can make the contact angle of the copper mesh reach 155 0.and explain the formation mechanism by analyzing the surface morphology and chemical composition of the copper mesh.The copper mesh prepared by the method can withstand strong acid,strong alkali,high salt,high temperature 200?,and the contact angle is still as high as 140 0 after the tape is peeled ten times.The separation efficiency of the copper mesh for the four oil-water mixtures is above 80%.The separation efficiency has not decreased with the increase of the number of cycles of use,and it has been successfully applied to the oil-water separator,and the separation efficiency is above 85%.(3)Preparation of superhydrophobic copper mesh by biomimetic coating.Different from the above two methods of directly reacting with the copper mesh,the method utilizes the adhesion of PDA to coat the copper mesh,and the PDA layer was used as a secondary reaction platform to successfully restore the silver nanoparticles to the surface of the copper mesh.The surface contact angle of copper mesh obtained by modification with 1-dodecanethiol can reach 155°.The XPS study showed that PDA,silver nanoparticles and 1-dodecanethiol were successfully modified to the surface of the copper mesh.The copper mesh prepared by this method can withstand a high temperature of 150? and has good resistance to strong alkali and salt solutions.And the separation efficiency of the copper mesh for the four oil-water mixtures is above 75%.