Preparation Of Superhydrophobicsuperlipophilic Composite Filter Membrane And Study On Its Water-in-oil Emulsion Separation Performance

The random discharge of oily wastewater will not only threaten the environment,but also waste resources.Some oils are non-renewable resources.Once recovered,most of them can be used comprehensively.Therefore,it is necessary and urgent to treat oily sewage and recover resources.Emulsified oil wastewater in oily wastewater has a small oil droplet size,which is the most difficult type to separate.How to effectively treat emulsified oil wastewater has become one of the urgent problems to be solved.A simple hydrothermal synthesis reaction and calcination method are used to prepare a ZnCo₂O₄ coating with ideal size micro-nano structure on the foamed nickel substrate.The micro-nano structure of the ZnCo₂O₄ particles is in the shape of a three-dimensional mesoporous flower,which greatly improves the surface roughness of the nickel foam.The ZnCo₂O₄ nickel foam that has not been modified by stearic acid presents a superhydrophilic and superlipophilic state in the air,but has excellent superoleophobic properties under water.Therefore,the coating is resistant to engine oil,vegetable oil,lower viscosity xylene and trichloromethane has good oil-water separation ability.The ZnCo₂O₄ coating modified by stearic acid has excellent superhydrophobic and superlipophilic properties,so the modified coating can be used to absorb oil in water.The oil absorption effect is remarkable,it is suitable for the surface treatment of sewage in factories and enterprises.Due to the ZnCo₂O₄ nickel foam is magnetic,therefore,magnets can also be used for oil absorption experiments under water.At the same time,the modified ZnCo₂O₄ nickel foam also has a certain separation effect on the oil-water emulsion,but the separation efficiency is low due to the large pores of the foam nickel.The ZnCo₂O₄ coating was again prepared on the stainless steel net with a base of2300 mesh by hydrothermal synthesis and calcination,and the coating was reinforced with TiO₂ sol to make the ZnCo₂O₄ micro-nano particles more tightly bonded,which not only further reduced the membrane pore size,it also enhances the stability of the filter membrane.The prepared ZnCo₂O₄/TiO₂ composite coating has good superhydrophobicity,super lipophilicity and excellent low adhesion properties in the air.At the same time,the coating has good recyclable performance,and can maintain good emulsion separation ability after repeated use.A polyvinylidene fluoride（PVDF）/polysulfone nanofiber membrane was prepared by electrospinning.It has excellent superhydrophobic and super lipophilic properties in the air,and the film is soft and tough,and the film surface has ideal low adhesion.PVDF/polysulfone nanofiber membranes can quickly and efficiently separate heavy oil from oil and water,and have good reusability.The filtration efficiency of dichloromethane,trichloromethane and carbon tetrachloride are as high as 99%,even after 10 cycles of filtration,it can reach a filtration efficiency of about 98.5%.Even under the action of gravity,the oil flux is larger,so the oil-water separation speed of this membrane is faster.Due to the extremely small pore size of the membrane,it has a good demulsification effect on water-in-oil emulsions,so PVDF/polysulfone nanofiber membranes can also filter vegetable oil,engine oil,diesel oil and kerosene emulsions with a filtration efficiency of 99%.In summary,the three preparation methods are simple,environmentally friendly,and the filter membrane has strong comprehensive performance,and has a good separation effect for water-in-oil emulsions.The paper has 48 map sheets,4 tables,and 107 references.