Fabrication Of Superhydrophobic And Superoleophilic Melamine Sponge And Study On Its Oil-water Separation Performance

In recent years,with the development of economy,people's demand for oil and other energy is increasing day by day.However,oil leakage and other accidents in the process of exploitation,transportation,storage and use will cause serious pollution to water resources.In order to handle these polluted water resources and to recycle oil products,an effective oil-water selective separation material is urgently needed for this purpose.In this paper,two superhydrophobic and superoleophilic melamine sponges and superhydrophobic silica powders were fabricated on the basis of melamine sponge,and a series of oil-water separation tests and various durability tests were carried out.Using the self-polymerization of dopamine hydrochloride and copper dodecarbide complex,the superhydrophobic and superoleophilic melamine sponge with flame retardant property was prepared.The results show that the surface of sponge is covered with a rough and uneven micro-nano structure,and contains S,Cu and other elements.The internal and external contact angles of the water droplets are 151.2° and 151.4° respectively,and the oil droplets can be completely absorbed into the sponge skeleton within 1s,realizing the superhydrophobic and superoleophilic characteristics.In addition,sponges have excellent absorption ability to oil products and organic solvents,which can reach 54?77 times of their own mass.Simulated oil-water separation experiments were carried out on rapeseed oil,kerosene,polydimethylsiloxane,soybean oil and engine oil,respectively,and the oil content in the water was 15.20mg/L,22.62mg/L,24.81mg/L,36.45mg/L and 40.85mg/L.The effect is better when the newly prepared unused superhydrophobic sponge is used to separate the same oil-water mixture.And the oil content of soybean oil can be reduced to 5.12mg/L after repeated 5 times.In acetone and hexane,the hydrophobic properties were still good at 6h.Moreover,it has good reusability,acid and alkali resistance and seawater corrosion resistance.More importantly,melamine sponge has excellent flame retardant properties compared to polyurethane sponges.A superhydrophobic and superoleophilic silica/melamine sponge was successfully prepared by modifying the method of Zhu et al.and replacing the substrate with a melamine sponge.The results show that the surface of sponge is coated with silica particles with micro-nano roughness.The contact angles of the sponges' internal and external skeleton droplets are 152±2° and 156±2° respectively,and the oil droplets can be completely absorbed by them within 0.7s,realizing the characteristics of superhydrophobic and superoleophilic.In addition,the sponge can absorb 70?92 times of its own mass of oil or organic solvent.Simulated oil-water separation experiments were conducted on soybean oil,lubricating oil,corn oil,kerosene and n-octane,and the oil content in the water reached 40.56mg/L,38.34mg/L,35.47mg/L,18.99mg/L and 15.47mg/L,respectively.When the newly prepared superhydrophobic sponge is used to separate the same oil-water mixture,the effect is better.When five tablets are used,the oil content can be reduced to 3.14mg/L,which has nothing to do with the initial oil content.In addition,it also has a good separation effect for emulsified oil.The sponge also has good reusability,good ultrasonic resistance and acid and weak alkali corrosion resistance.The reaction solution in chapter 4 was centrifuged and the reaction solid particles were extracted to obtain superhydrophobic and superoleophilic silica powder.As a result,the surface contact angle with water droplets can reach 152.4° and has low adhesion.The oil droplets can be completely absorbed by them within 5.94 s,achieving superhydrophobic and superoleophilic properties.The powder is mainly spherical,with a diameter between 400 and 500 nm.It has good application in oil pollution field limited by space.