The Fabrication Of Superhydrophobic/Superoleophilic Mesh And Its Application In Oil/Water Separation

Based on the wetting theory of solid surface,superhydrophobic-superoleophilic surface on stainless steel mesh substrate was constructed by two different methods in this dissertation.The hydrophobic and oleophilic mechanism was studied and its application in oil/water separation was explored.The main research works are outlined as follows:1.A multi-level rough structures on the surface of stainless steel mesh was obtained by chemical etching.After chemical etching,the surface of the stainless steel mesh was evenly covered with massive bumps and grooves,forming a micro-structure analogous to the surface of the lotus leaf under the microscope.The size of these massive bumps is about 1²?m.Moreover there are many smaller granular bulges in the grooves,these bulges with different sizes formed a multi-level rough structures with different roughness.2.Nano-Ag particles were formed on the surface of rough stainless steel mesh through oxidation-reduction reaction and deposited on the bumps and grooves.Superhydrophobic-superoleophilic stainless steel mesh was obtained after the stearic acid was used to reduce the surface energy.The hydrophobicity mechanism of Ag-stearic acid on stainless steel mesh was analyzed.The effects of nano-Ag particles modification time and stearic acid modification time on the wettability of stainless steel mesh were investigated by measuring the water contact angle and rolling angle.The water contact angle of Ag-stearic acid modified stainless steel mesh was 144°and the oil contact angle was 0 after placed in air for 30 days,shows high hydrophobicity and superoleophilicity,indicating that the Ag-stearic acid modified stainless steel mesh has great stability.3.Hexadecyltrimethoxysilane?HDTMS?modified SiO₂ was prepared by improved St?ber method.The HDTMS-SiO₂ sample has good dispersibility,uniform particles size,and the particle size range from 300 to 500 nm.The HDTMS-SiO₂ sample exists in an amorphous structure and is typical disordered amorphous SiO₂.Long alkyl chains of HDTMS grafted onto the SiO₂ surface,giving the HDTMS-SiO₂ particles special wettability.Superhydrophobic-superoleophilic stainless steel mesh was obtained by deposited HDTMS-SiO₂ on the surface of rough stainless steel mesh surface.The effects of the modification time and particle size of HDTMS-SiO₂ on the wettability of the stainless steel mesh surface was investigated by measuring the water contact angle and rolling angle.The water contact angle of HDTMS-SiO₂ modified stainless steel mesh was145°and the oil contact angle was 0,maintained high hydrophobic superoleophilicity after exposed to air 30 days,indicating that the prepared HDTMS-SiO₂ modified stainless steel mesh has good stability.4.The oil-water separation performance of Nano-Ag modified stainless steel mesh and HDTMS-SiO₂ modified stainless steel mesh was studied.The results shows that the Nano-Ag modified stainless steel mesh has good oil/water separation performance,durability and corrosion resistance.The HDTMS-SiO₂ modified stainless steel mesh has great corrosion resistance,durability and scratch resistance,and can efficiently separate a mixture of strong acids,strong bases and kerosene,and can be used in harsh environments.