Preparation And Properties Of CPVA-PVDF/PMMA/GO Janus Superhydrophobic Nanofiber Membrane Based On Electrospinning

Petroleum has provided great impetus for the progress of science and technology and the development of society.But at the same time,the oily wastewater discharged by industry has also caused huge damage to the human ecological environment.In recent years,oil spill accidents and oily wastewater discharges have occurred frequently,causing huge economic losses and a huge impact on the ecological environment.At present,many technologies have been developed for oil-water separation,such as centrifugation,adsorption,precipitation,membrane separation,etc.Compared with traditional oil-water separation technologies,membrane-based oil-water separation methods have received extensive attention due to their simple preparation,mild operation,and relatively low cost.The ideal nanofiber membrane for oil-water separation should have the characteristics of high flux,high separation efficiency,recyclability,and good mechanical stability.Among all the methods for fabricating oil-water separation membranes,electrospinning is widely used to produce nanofiber membranes with high porosity because of its technical simplicity and low cost.The high porosity formed by the interweaving of the fiber network ensures that the electrospun fiber membrane has some outstanding features,such as high liquid permeability and high separation efficiency,compared to the fiber membrane obtained by other techniques.In addition,the hierarchical porous structure of the electrospun fiber membrane delays the clogging of pores,making it inherently anti-fouling.As a new type of separation membrane,Janus nanofiber membrane has great development potential in oil-water separation,distillation and other fields.In this paper,PVA and PVDF/PMMA/GO nanofiber membrane was prepared based on electrospinning technology,and the cPVA-PVDF/PMMA/GO Janus superhydrophobic nanofiber membrane was prepared by compounding the hydrophilicPVA fiber membrane and the hydrophobicPVDF/PMMA/GO fiber membrane,and the properties of the composite nanofiber membrane were studied.A simple and novel preparation method of superhydrophobic Janus membrane is proposed for the increasingly serious problem of oil-water separation,which has a very bad influence on environmental pollution and resource recycling.The cPVA-PVDF/PMMA/GO Janus superhydrophobic nanofiber membranes with opposite hydrophilic and hydrophobic properties were prepared by layer-by-layer electrospinning method.The structure of Janus nanofiber membrane is as follows:first,a mixed solution of polyvinylidene fluoride（PVDF）,polymethyl methacrylate（PMMA）and graphene oxide（GO）was electrospun to form a hydrophobic layer,and then polyvinyl alcohol（PVA）nanofiber membrane was electrospun layer-by-layer onto a hydrophobic membrane to form a composite membrane,and finally the composite membrane was cross-linked to obtain a Janus membrane.The addition of graphene oxide can significantly improve the hydrophobicity,mechanical strength and stability of the Janus nanofiber membrane,and at the same time has a strong flexibility,which can be restored to its original state in the case of bending,folding and other deformations.In addition,after several oil-water separation experiments,the prepared Janus nanofiber membrane still maintains good oil-water separation performance,and the separation efficiency hardly decreases.The prepared Janus composite nanofiber membrane has extremely high flux,and at the same time,the separation efficiency and durability are good.The flux in the oil-water separation process can reach 1909.9 m^-2 h^-1,and the separation efficiency can reach99.9%.Compared with other Janus membranes,it has obvious advantages in terms of separation efficiency and separation efficiency.At the same time,the Janus composite nanofiber membrane can also separate water-in-oil emulsions and water-in-diesel emulsions without pollution and damage during the separation process,which not only proves the separation effect of the nanocomposite membrane,but also shows high stability and recyclability.The asymmetric Janus membrane has good oil-water selectivity and has broad application prospects in many fields.The prepared cPVA-PVDF/PMMA/GO Janus composite nanofiber membrane has excellent filtration performance,can more effectively retain tiny particles,and at the same time,the pressure drop of the fiber membrane is also very low.The results show that the cPVA-PVDF/PMMA/GO Janus composite nanofiber membrane has great permeation potential,which further expands the potential applications of the as-prepared cPVA-PVDF/PMMA/GO Janus composite nanofiber membrane.