Utilizing Special Wettability Of Silicon-based Materials For Oil-water Separation Under Complex Conditions

Recently,the utilization of superwetting materials for oil-water separation has drawn great attentation in the research field.Superoleophilic/superhydrophobic and superhydrophilic/underwater superoleophobic materials are fabricated based on the wettability of materials with the formation of micro-nanostructures on the surface.Such prepared materials open an alternative pathway for efficient separation of oil-water mixtures compared with traditional methods.However,state-of-the-art oil-water separation materials stay far from the requirements due to complicated situations,including emulsion separation,harsh conditions of separation and controllable recycle of impurities in water,which remain significant challenges for the development of superwetting materials.Silicon-based materials are considered as an optimal precursor for oil-water separation under complex conditions,which mainly attributed to their excellent corrosion resistance and surface modifiable capability.In this work,materials have been designed targeting at:(1)separation of water-in-oil emulsions;(2)oil-water separation under harsh environments;(3)separation of oil-in-water emulsions under harsh environments and(4)efficient adsorption of DNA in water.Corresponding details as follows:A high-performed magnetically recoverable demulsifier is fabricated to efficiently demulsify surfactant-stable water-in-oil emulsions.Fe3O4 particles are firstly coated by amorphous SiO2,and further functionalized by dodecyltrimethoxysilane.Such demulsifier particles with core-shell structure present hydrophobic features and can be easily recovered with a magnet.Water-in-oil emulsions are dmulsified by addition of the demulsifier.Moreover,magnetically recovered demulsifier is regenerated after simple treatment without any decline of efficiency.A superhydrophilic and underwater superoleophobic mesh with micronanostructures on the surface is prepared by coating quartz fiber with silica gel.Driven by gravity solely,the as-prepared mesh can separate oil-water mixtures with high efficiency in strong acidic and high salt conditions.A superhydrophilic and underwater superoleophobic surface is fabricated by simply coating silica nanospheres onto a glass fiber membrane via a sol-gel process.The constructed membrane with a composite micro-nanostructure exhibits outstanding stability under both strong acidic and concentrated salty conditions,therefore,achieving an excellent oil-in-water emulsion separation capability under harsh environments.A composite membrane coated with mesoporous silica nanoparticles(MSNs)has been developed for DNA adsorption.The preparation conditions of aminofunctionalized MSNs are optimized to balance high surface area,appropriate porosity,and selective absorption of DNA.Inspired by water-treatment field,we coat resultant MSNs on glass-fiber membranes to fabricate superhydrophilic composite membranes.These composite membranes can efficiently filtrate DNA aqueous solution.Desorption of DNA is accomplished simply by immersing the membranes in alkaline solution.