| Oil water pollution not only causes waste of energy,but also brings great harm to the ecological environment.To solve the problems,filter membranes and adsorption materials with special wettability have been prepared.It is found that special wettability can be controlled by adjusting the surface roughness and surface chemical composition.The successful preparation of the material is a great significance for environmental protection and water conservation.But most work uses chemical agents as raw materials,which is easy to cause pollution to the environment.At the same time,most of the substrates are metal or organic polymer substrates,which have the disadvantages of poor flexibility or low mechanical strength.In view of the above two problems,waste cloths and high silicon cloth are selected as the base materials,and oil-water separation membranes are prepared by different modification methods.Two kinds of special wettability membranes are prepared to meet different requirements for oil-water separation.The research content of this paper is as follows:（1）Most of the current work use commercial materials and chemical agents,and a large number of solid wastes becomes environmental burden.According to above problems,the superhydrophobic separation membrane is prepared by waste cloth,waste polystyrene（PS）foam box and nano Si O2.Waste cloth is used as the substrate,waste PS foam box as low surface free energy raw materials,and nano Si O2as roughness material.By changing the concentration of PS and Si O2,the membrane with the best hydrophobic performance is obtained（named 80-PS/2-Si O2@Cloth）.Its water contact angle reaches 153°,which can be used for the separation of peanut oil and water mixture,and the separation efficiency is92.7%.Furthermore,another layer of PDMS is coated to solve the problem that the PS layer can be dissolved by organic solvents such as methylene chloride and gasoline.The influence of its concentration on the hydrophobic performance and separation efficiency is studied.The results show that the optimal performance is achieved with water contact angle of 158°when the concentration of PDMS is 150 mg/m L.Its separation efficiency of dichloromethane-water mixture is up to 98.8%and after 20 cycles the separation efficiency is still 97%.It also can separate other oil-water mixture.The separation efficiency of n-hexane,gasoline,dichloromethane,peanut oil and pump oil is more than 93%.In addition,the modified cloth membrane coated by PDMS has good chemical and mechanical stability.（2）Super-hydrophobic/super-oleophilic oil-water separation materials often suffer the problems such as easy pollution,fragile and not resistant to acid and alkali.To solve this problem,we use high silicon cloth（HSC）as the substrate which has the advantages including high mechanical strength,good flexibility,superior heat and acid resistances.Typically 3-aminopropyl triethoxysilane（APTES）is used as the"double-sided adhesive"graft on its surface:nano Si O2is deposited on one side by electrostatic interaction to provide surface roughness,and polydopamine（PDA）with strong hydrophilicity is polymerized on the other side.As a result super hydrophilic/underwater oleophobic high silica cloth（named APTES/Si O2/PDA@HSC）membrane is obtained.The effects of APTES concentration,Si O2size and concentration,and polymerization time of PDA on oil-water separation performance are studied.The best oil-water separation performance of modified HSC is obtained when APTES concentration is fixed as 4%,the concentration of 50 nm Si O2is 4mg/m L,and polymerization time is 24 h.The oil-water flux of gasoline-water mixture on APTES/Si O2/PDA@HSC membrane is 7184 L/（m2·h）,and the separation efficiency is 98%.Furthermore,separation efficiency is still more than 97%after 10 cycles.It is also used for oil-water separation of other oil-water mixture such as peanut oil and pump oil.The super hydrophilic/underwater oleophobic membrane is highly stable,and resistant to acid,alkali and salt solution. |
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