Preparation Of Stainless Steel Composite Filter Membrane And Study On Its Separation Performance Of Emulsions

The traditional oil-water emulsion separation method requires external driving force,the process is complicated.It is imperative to study the new emulsion separation technology,the rapid development of membrane separation technology provides convenience for oil-water separation.In this paper,a simple chemical oxidation polymerization method,a chemicaldeposition method and a low-temperature hydrothermal synthesis method are used to construct a rough structureonthesurfaceofstainlesssteelmeshtopreparea superhydrophilic/underwater superoleophobic stainless steel mesh for oil-water and oil-in-water emulsion separation.The micro-nano polypyrrole coating was polymerized on the surface of stainless steel mesh by chemical oxidative polymerization.It has superamphiphilicity in air,and the chloroform contact angle underwater is 158.5°±1.5°.After being soaked by strong acid,strong alkali and saturated saline solution for 24 h,it still maintained good underwater superoleophobicity and stability.Under gravity,the coated stainless steel mesh effectively separates oil or water from various oil-water mixtures with a separation efficiency of>97%.It has good recyclability under various harsh environments,and the separation efficiency is 95.8%after 30 cycles.FeCl₃ is the best oxidant,and?NH₄?₂S₂O₈ can quickly prepare a large number of coated stainless steel mesh for mass production.A uniform tungsten oxide coating was prepared by chemical deposition method.The WO₃/TiO₂ composite coated stainless steel mesh with high strength was obtained by dip coating titanium dioxide sol.It has underwater superoleophobicity,low adhesion and after friction under 20 kPa pressure,it still maintained good underwater oleophobicity and high separation efficiency.It has good separation effect on different types of oil-in-water emulsions,and the separation speed is fast.The water flux under gravity is about 200 L·m^-2·h^-1,exceeds 1200 L·m^-2·h^-11 at 0.1 MPa,the separation efficiency is greater than 98.5%,after repeated cycles,the separation efficiency is greater than 96%.The composite coating has good anti-staining properties.When the water flux is reduced,the water flux can be restored to the initial value after rinsing with alcohol.The zinc oxide coating was prepared by low temperature hydrothermal synthesis and calcined with TiO₂ sol to prepare superhydrophilic/underwater superoleophobic ZnO/TiO₂ composite coated stainless steel mesh.The underwater chloroform contact angle was 154.5°±0.8°.TiO₂ forms a dense oxide film on the surface of ZnO coating,which improves the acid and alkali corrosion resistance of the coating.After soaking for 12 hours in acid-base solution,it still has good underwater oleophobic performance.The composite coating has good separation effect on different kinds of oil-in-water emulsions,and the separation speed is fast.The water flux under gravity is about 500 L·m^-2·h^-1,and more than 1500 L·m^-2·h^-11 at 0.05 bar,the separation efficiency is greater than 98.5%.The acidity and alkalinity of the emulsion had little effect on the separation efficiency,but after 12 hours of acid-base soaking treatment,the separation efficiency of the neutral emulsion was reduced,and the reduction after alkaline soaking was greater than the acidic condition.The composite coating has a certain separation effect on hyperlipidemia blood lipids separation.In summary,PPy,WO₃/TiO₂ and ZnO/TiO₂ composite coated stainless steel meshes have simple preparation process,low cost and no pollution,which provide an effective method for efficient,green and rapid separation of oil-water mixtures and oil-in-water emulsions,among which ZnO/TiO₂ composite coated stainless steel mesh provides basic research for the separation of blood lipids.