Wettability Of Nano-metallic Oxides And Further Application In Water Treatment

Wettability is one of the most important properties of solid materials,which is mainly determined by the chemical composition and the micro structure of the surface.By the methods of surface phase control,bioinspired intelligent nanostructured interfacial materials have been designed with many interface effects.Materials with special wettability,like superhydrophilic,superhydrophobicity,superoleophilicity,and superoleophobicity,are developed by the combination of those features,which have potential in applications of many different fields,especially for water treatment.Materials with special wettability can be used in oil/water separation,but when it comes to emulsions,the separation of emulsified oil/water mixtures can be a real challenge.Components of emulsions are much more complex than simple oil/water mixtures,where multiple molecular interactions occur,and surfactant can react between water molecules and oil molecules to form a stabilized system.Membranes made of polymers provide corresponding solutions,the contradiction between flux and efficiency is difficult to balance since the separation process needs to be driven by external pressure.Moreover,in order to provide membranes with special wettability and proper pores,the preparation method is sometimes multi-stepped and hard to control.Pure inorganic nano-metallic oxides may give a brand new way of emulsion separation.Fabricated by easier and cost-efficient ways,such inorganic membranes could combine the special wettability and their specific features,like photocatalytic activity and electric responsiveness,which can be applied for the efficient separation of various types of emulsions as well as other water treatments.The problem still need to be addressed is the large pore size versus porosity,which determined by the growth of metallic oxides.Herein,using nano-metallic oxides,such as ZnO,TiO₂,and SnO₂,meshes with special wettability were achieved through multiple methods,and further attempt to solve the separation problems.In this work,a ZnO-Co₃O₄ overlapped mesh was prepared and successfully used for efficient separation of both surfactant-free and surfactant-stabilized emulsions solely driven by gravity.A TiO₂ nanocluster-based mesh was constructed and successfully worked on emulsion separation and soluble contaminants degradation under UVillumination in one step,with extremely high flux and efficiency,which provides a new way to develop multifunctional materials for potential use in water remediation.A SnO₂-CNTs coated mesh was fabricated and successfully presented electricity-induced switchable wettability between hydrophobicity and superhydrophilicity under a relatively low voltage with rapid responsiveness and reversibility.They have shown great potential applications in the field of water treatment,intelligent device and so on.