Construction Of Hierarchical Structure Of Titanium Dioxide And Their Performance Study In Oil/water Separation

A large amount of oily wastewater has caused serious ecological and environmental problems.Compared with traditional separation methods,the development of bioinspired materials with special wettability for oil-water separation has obvious advantages.Among them,superhydrophilic and underwater superhydrophobic interface materials,inspired by the surface of mussel and fish scale,have become the current research hotspot because of their unique underwater anti-oil pollution and self-cleaning properties.The superhydrophilic titanium foam and stainless steel mesh were prepared by in-situ growth method based on the construction of titanium dioxide multistage structure on different substrates.The details are as follows:A vertical micro/nano structure was constructed on the surface of porous titanium foam by hydrothermal method.Super stable Ti O₂ nanoarrays were prepared by ion exchange and calcination.The change of surface morphology of titanium foam with different reaction time was analyzed,and we revealed the possible formation mechanism of Ti O₂ structure.Based on the morphology and contact angle test,the optimum reaction time was chosen to prepare superhydrophilic titanium foam for separating oil-in-water emulsion.The separation efficiency of all kinds of oil in water emulsion was over 97.5%.In addition,because the stable enough structure of in-situ grown Ti O₂,its mechanical stability was very good,which can maintain special wettability and structural integrity under ultrasonic vibration and mechanical friction.And it was resistant to corrosion of strong acid,alkali,salt solution and a variety of organic solvents.The experiment of underwater oil pollution showed that superhydrophilic titanium foam had excellent oil resistance and self-cleaning ability.The Ni O@Ti O₂ heterostructure on the surface of steel mesh was fabricated by hydrothermal method and liquid phase deposition,which endowed the mesh with special superhydrophilic wettability and photocatalytic ability.The surface of stainless steel was treated by hydrothermal reaction and calcination to form Ni O microflakes.The Ti O₂ nanoparticles were uniformly anchored on the Ni O microflakes by liquid phase deposition.The as-prepared superhydrophilic stainless steel mesh had excellent underwater superhydrophobicity,which can separate a variety of oil-water mixtures,while maintaining high separation flux and efficiency.In addition,the heterostructure on the surface of superhydrophilic stainless steel mesh had excellent mechanical and chemical stability.It can still maintain a complete morphology under ultrasound and turbulence disturbance,and can resist the corrosion of acid,alkali and salt solutions.Moreover,this kind of superhydrophilic material can degrade dyes under visible light,which open a new avenue to prepare multifunctional water treatment membrane.