Preparation Of Special Wettability Materials And Their Application In Water Pollution Environmen

With the rapid development of industry and urbanization,the discharge of oily wastewater has increased sharply,which not only poses a serious threat to marine environment and aquatic ecosystem,but also causes pollution to underwater materials and causes huge economic losses.Therefore,it is urgent to seek efficient methods to treat oily wastewater.In recent years,the special wettable materials inspired by lotus leaves have attracted attention in the field of oil-water separation.The use of special wettable pore/mesh materials with different affinity for water/oil to achieve oil-water separation has become a new idea for the treatment of oily wastewater.In addition,the superhydrophobic-superoleophobic material can effectively reduce the corrosion and pollution of the corrosive liquid to the matrix by using the air film stored on the surface.Therefore,based on the super-infiltration theory and practical requirements,and on the basis of the development status of the preparation technology of the special infiltration surface interface,this paper firstly prepared the superhydrophobic-superoleophilic polyvinyl alcohol sponge（PVA）which could separate the heavy oil-water mixture by using one pot hydrothermal method.In order to further separate oil-water mixtures of various densities,superhydrophilic-underwater superoleophobic stainless steel mesh was prepared by electrodeposit-modification method which could separate heavy/light oil-water mixtures.In order to prolong the service life of special wettable materials in harsh water environment or to provide possibilities for the processing of oil-bearing device after oil and water separation,the superhydrophobic-superoleophobic copper base materials with excellent antifouling and anticorrosion performance were prepared by electrodeposition-modification method to prolong the service life of metal matrix in marine environment.（1）A superhydrophobic-superoleophilic polyvinyl alcohol sponge modified by stearic acid/nano-Ti O₂ particles（referred to as STt@PVA,where S,T and t denoted stearic acid,nano-Ti O₂ particles with diameters of 50 nm and 20 nm,respectively）was constructed by one-pot hydrothermal method for oil and water separation.The results showed that the water contact angle（WCA）of STt@PVA was 163°,the water slip angle（WSA）was less than 3°,and the oil contact angle（OCA）was 0°.The oil and water separation results showed that the oil and water absorbed by the modified sponge is 5～8times of its own mass.After repeated use for 5 times,the sponge can still maintain the oil absorption capacity of 5 times its own mass,and the separation efficiency remained above 83.0%.In addition,the reasonably designed superhydrophobic-superoleophilic functional PVA sponge had the advantages of simple preparation,low cost,recyclability and strong robustness,which had great application potential in the treatment of heavy oil-water pollutants.（2）In order to adapt to different oil-water separation conditions,the stainless-steel mesh（SSM）was used as the substrate.Firstly,Cu was electrodeposited on the SSM to improve the surface roughness,and then polytetrafluoroethylene（FS-50）was used as the modifier to change the wetting state of Cu coating.The superhydrophilic-underwater superoleophobic SSM（CF-SSM）which can be used to separate light/heavy oil-water mixtures was prepared.The results displayed that functional SSM had low adhesion to oil both in air and underwater,where the OCA was up to 160°.In the oil-water separation test,the separation efficiency of superhydrophilic-underwater superoleophobic SSM for different kinds of oil-water mixture was between 97.5%and99.3%.After separating n-hexadecane-water mixture for 10 times,the separation efficiency can reach more than 98.6%.In addition,the superhydrophilic-underwater superoleophobic SSM also had advantages of strong mechanical stability,acid and alkali resistance.This work provides a new idea for the preparation of low-cost and mechanically stable superhydrophilic-underwater superoleophobic oil-water separation membranes.（3）On the basis of the above research,in order to further improve the service life of special wettable materials in harsh water environment or to provide possibilities for the processing of oil-bearing device after oil-water separation,the nickel/copper（Ni/Cu）alloy surface with layered micro/nano structure was prepared on the brass substrate by controlling the generation of particles during the electrochemical co-deposition of nickel and copper ions.Then,the Ni/Cu alloy（NCA）surface was modified by1H,1H,2H,2H-perfluoroalkyl trimethoxy-silane（PFDS）,which made the PFDS/NCA（PNCA）composite surface had excellent superhydrophobicity-superoleophobicity.The structure and properties of PNCA coating were evaluated and described by various methods.The wettability test showed that the WCA of water and OCA on the optimal PNCA surface were 163°and 155°,respectively,and the SA was less than 10°.After a series of performance tests,the optimal PNCA surface displayed good mechanical stability,antifouling and chemical stability.In addition,compared with NCA coating,the anticorrosive efficiency of PNCA coating increased to 91.73%.In conclusion,the superhydrophobic-superoleophobic PNCA composite surface prepared by electrochemical co-deposition combined with modification of low surface energy materials has a wide application prospect in harsh water environment.