Preparation Of Extreme Wetting Mesh For Oil/Water Separation By Electro-Brush Flow Plating

The continuous emission of industrial wastewater,domestic sewage and the frequent occurrence of oil spills at sea led to a large amount of oil/water mixture,which caused great harm to the environment and human health.Therefore,the study of oil/water separation has great social significance and economic value.The extreme wettability surface is the surfaces with contact angles more than 150 ° or the contact angle less than 10 °.It has broad application prospects oil/water separation and other fields.Most of the existing methods for the preparation of extreme wetting surfaces for oil/water separation have many problems,such as low surface strength and poor wear resistance.Therefore,this paper proposes a method to prepare extreme wetting mesh for oil/water separation by electro-brush flow plating.The main work and research results of this paper are as follows:The technological process of preparing extreme wetting surface by electro-brush flow plating is explored and optimized.The superhydrophilic-superoleophobic underwater surface was successfully prepared on the stainless steel mesh by using nickel sulfate and other reagent as electroplating solution.And the superhydrophobic-superoleophilic surface was obtained after simply putting the superhydrophilic and superoleophobic underwater surface into stearic acid ethanol solution.The effects of brush plating voltage,brush plating time and brush plating speed on the contact angle and rolling angle of the stainless steel mesh surface were studied.The best superhydrophobic surface is obtained when the brush plating voltage is 16 V,the brush plating time is 5 min and the brush plating speed is 8 m/min,at this time the contact angle is up to 158 °,and the rolling angle is 6 °.The microstructure and chemical composition of the stainless steel mesh surface after plating were analyzed by scanning electron microscope,X ray photoelectron spectroscopy analyzer and X ray diffractometer.The results show that the surface elements of the coating are mainly nickel,and there are a large number of micro and nanoscale mastoid structures,cracks and pits on the surface of the coating.These microstructures make up the micro and nano dual rough structures necessary for the extreme wetting surface.The effect of the process parameters,such as voltage,time and speed,on the surface micromorphology of the coating surface was studied.The results showed that with the increase of the brush plating voltage,the mastoid structure on the stainless steel mesh coating gradually increased and the grain gradually refined.With the increase of brush plating time,the grain size of the coating was gradually refined.With the increase of brush plating speed,the mastoid structure on the surface of the coating decreases.The comprehensive performance of superhydrophobic coating was tested.The results show that the coating surface has good self-cleaning ability and the strong friction resistance.The coating surface has a good bending resistance.After repeated bending,the coating has no scaling,dropping.The surface of the coating has good stability,and it can still maintain superhydrophobicity after 120 days.The extreme wettability mesh was used for oil/water separation experiments.The effect of brush plating voltage and different initial water content on the oil/water separation efficiency of superhydrophobic-superoleophilic mesh was studied.The superhydrophobic-superoleophilic mesh has good separation effect on the mixture of heavy oil(dichloromethane)and water,and the separation efficiency is over 99.5%.And the superhydrophilic-superoleophobic underwater mesh shows excellent separation effect on the mixture of light oil and water,such as sixteen alkane,hexane,diesel and peanut oil,and the separation efficiency can reach more than 98%.