Fabrication Of Superhydrophobic-Superoleophilic Stainless Steel Meshes And Their Applications In Oil-Water Separation

With the development of the industrial society,the problems of environment and pollution have been paid more and more attention to.Currently,oily sewages in the industrial production,frequent oil leakage and oil spills not only lead to serious economic issues and waste of energy,but also pollute the ecosystem severely.Thus,how to separate oil and water from oily sewages has aroused wide concern.Recently,materials with super wettability have been research hotspots in the field of oil-water separation.Superhydrophobic-superoleophilic materials,for example,have different affinities for oil and water,which oil can get across easily but water can't,so oil and water can be spontaneously separated.In this paper,we chose stainless steel meshes as substrates,and fabricated superhydrophobic-superoleophilic meshes via spray for oil-water separation.The main research contents are as follows:(1)A POSS hybrid acrylic polymer,P(MMA-SMA-MAPOSS),was synthesized via a free radical solution polymerization and characterized by FTIR,~1H NMR and TGA.Then,P(MMA-SMA-MAPOSS)was dissolved in ethyl acetate with ethyl-?-cyanoacrylate,and the mixture was sprayed onto the mesh.Finally,a superhydrophobic-superoleophilic mesh was obtained.Besides,the possible mechanism of forming this superhydrophobic-superoleophilic mesh was explained with the characterization of SEM and XPS,and the effect of the filter pore size on the hydrophobicity of the filter is also explored.The coated mesh with the ideal size has a high static water contact angle of 153°and a low sliding angle of 4.5°,and can be applied to separate a series of oil–water mixtures with separation efficiency nearly 99%.In addition,the coated mesh still kept separation efficiency approximately 99%even after 25 separation cycles for n-hexane-water mixture.Moreover,linear wear test had been used to demonstrate that the hydrophobic coating had favorable mechanical stability.(2)Halloysite nanotubes(HNTs)were transformed from hydrophilic to hydrophobic with modification of hexadecyltrimethoxysilane(HDTMS).Then,HDTMS-HNTs were mixed with epoxy resin,and the mixtures were sprayed onto the stainless steel mesh.Finally,the superhydrophobic-superoleophilic mesh was obtained.The effects of coating morphology and pore size of mesh on the hydrophobicity of the coating are studied by SEM and optical contact angle measuring device.The mesh with the ideal size has a high static water contact angle of 154°and a low sliding angle of1.5°.In addition,it not only could separate a series of oil-water mixtures with high separation efficiency of over 98%,but also could keep separation efficiency approximately 98.5%even after 25 separation cycles.Meanwhile,tests of hot oil-water mixture,acid-base salt solution and sand impact prove that the obtained super-hydrophobic mesh has good thermal stability,chemical stability and mechanical stability,because the coated mesh can resist hot water,strong acid,strong alkali,sand impact and high hydrostatic pressure.This mesh is possible to be applied to large-scale oil-water separation,due to the simple,economical easily scalable,and universal fabrication method.