Preparation Of Super-wetting Ti-based Micro-nano Composite Membrane And Its Application In Purification Of Oily Wastewater

Water shortages and serious water pollution are two major problems in the "water" of countries.Therefore,how to deal with the problem of water pollution,especially the oily polluted water produced by industrial pollution and "arine crude oil leakage,is the focus of environmental researchers.There have been many traditional separation techniques in the past,such as eentrifugal separation,suspension technology,and electrochemical treatment.However,these technologies have the disadvantage of long processing time,cumbersome operation,low separation efficiency,and secondary pollution.In recent years,with the in-depth exploration of the principles of bionics,researchers have given super-wetting properties to general natural and industrial materials.At the same time,with the help of new preparation methods,such as high-voltage electrospinning,hydrothermal synthesis,sol-gel,etc.,the researchers have developed super-wetting micro-nano composite materials for efficient oil-water separation,showing great application prospects.According to the separation method,these materials can be divided into two types:filter type separation materials and absorption type separation materials.The filter type separation materials can efficiently separate oil-water emulsion,and the absorption type separation materials can treat large-area polluted water body.However,there are still many areas for improvement in these materials,such as high cost,single material function and insufficient anti-pollution performance.In response to these shortcomings,a highly efficient and multifunctional filtration type separation membrane was prepared by a simple,low-cost method.On the basis of titanium(Ti)-based materials,it is compounded with popular materials such as graphene(GO)and cobalt tetraoxide(Co3O4)to construct a composite separation membrane with multiple micro-nano structures with super-wetting properties,thereby achieving synergistic purification of oil-containing wastewater.(1)Firstly,a brass mesh was used as a substrate,and a titanium dioxide(TiO2)nanorod array network having photocatalytic properties was obtained by a secondary hydrothermal method.In addition,the graphene oxide is sulfonated,and the sulfonated graphene oxide has enhanced hydrophilicity and water thickness,and the silver(Ag)nanoparticles are uniformly dispersed on the surface of the sulfonated graphene oxide(SGO)to improve the photocatalytic performance.Finally,vacuum filtration is used to achieve the combination of the two.The TiO2@SGO/Ag nano-particle micro-nano structure composite membrane has the property of simultaneously separating and photocatalyzing the oil-water emulsion containing organic dye.(2)In order to further improve the emulsion separation effect,a stainless steel mesh was used as a base,and a needle-like Co3O4 nano-needle was modified on the surface by hydrothermal method.The ultra-long sodium titanate nanowires are prepared by a special high-speed stirring hydrothermal method.The Co3O4 nano-needle mesh is used as the lower layer,and the sodium titanate nano-filament is used as the upper layer,and the uniformly covered sodium titanate nanowire/Co3O4 nano-needle double-layer micro-nano structure net membrane obtained by vacuum deposition can achieve high-efficiency separation of the micro-nano particle size oil-water emulsion.(3)Separating from the metal substrate,using TiO2 nanowire as the main body,the polyethyleneimine(PEI)is wrapped on the surface of the TiO2 nanowire by chemical bonding.The self-assembly method is used to prepare a composite of TiO2 nanowires and PEI into a self-supporting micro-nano composite membrane.The membrane has the function of separating oil-water emulsion and self-cleaning with high efficiency,and has certain reference value for improving the anti-pollution and durability of the separation membrane.