Modification And Aerogel Construction Of Nanofibers And Their Application In Oil-Water Separation

Oil pollution has become an urgent issue in the environmental field,so the rapid and efficient separation of oil and water is essential.The current researches on the oil-water separation mainly focus on two directions:oil-water adsorption materials and oil-water filtration materials.Membrane filtration method is usually simple to operate,which has high separation efficiency,large processing flux,and can be used for industrial production.Porous adsorption materials always have large specific surface area,high porosity and high adsorption capacity which take natural advantages in marine oil recovery.Based on this,our research topic is aimed at the problem of petroleum pollution.The nanofibers prepared by electrospinning method are used as the substrate to construct membrane and aerogel functional materials for high-efficiency oil-water separation.The main research results are as follows:?1?A hydrophilic monomer acrylic acid was grafted onto a low temperature plasma treated electrospun polystyrene/polyacrylonitrile film to prepare the nanofiber membrane having a superhydrophilic and underwater superoleophobic surface.Plasma treatment enriched the surface of the membrane with free radicals,which facilitated the subsequent grafting process.The contact angle measurement indicated that the surface of the grafted membrane was superhydrophilic?0°?.The grafted membrane has a high specific surface area of up to 17.8 m²/g,which is advantageous for increasing the contact area of the membrane with the liquid.After being pre-wetted by water,the membranes exhibit superoleophobicity,which can prevent oil droplets from sticking in water,and exhibit good antifouling properties.The gravity-driven filter device was used to test the performance of the membrane for oil-water separation.The graft membrane can efficiently separate the layered oil-water mixture and the surfactant-free oil-in-water emulsion.The permeation flux can reach 57509 and 6460 L m^-2 h^-1 respectively.The prepared membranes show high flux and excellent separation after multiple cycles of filtration experiments.In addition,the membrane still has good separation performance for the oil-water mixture in a corrosive water environment?acid,alkali and salt solution?.?2?Pretreatment of cellulose nanofiber suspension by directional freezing technology with regenerated cellulose,sodium alginate and collagen as raw materials,followed by ion crosslinking and silanization modification of the obtained product to prepare light quality,flexible,hydrophobic/lipophilic functional aerogel material.A regular and uniform parallel layered porous structural frame can be observed by SEM.The nanofibers interspersed therein to form a“honeycomb”three-dimensional structure,which is advantageous for improving the mechanical stability of the aerogel.The cross-linking modification process increases the aerogel compression-resilience,allowing it to quickly return to its original shape after 50%deformation.MTES as a silylation reagent successfully imparts superhydrophobic properties to aerogels.For kerosene,liquid paraffin and soybean oil,the aerogels can be effectively used for the separation of oil-water mixtures with an oil absorption capacity up to 30⁴2 g/g.