Preparation And Properties Study Of Nanocarbon Material/polysulfone Composite Membrane

Compared with the traditional water treatment technology,the membrane process is a separation technology with low energy consumption and high efficiency,which can be used for the depuration and purification of seawater,surface water,groundwater and even contaminated water sources.The reliability of contaminant interception,the flexibility of membrane material preparation,and the process is simple and easy to control,so membrane technology is considered to be an effective water treatment process.Polysulfone?PSF?is a film-forming polymer with excellent performance.Due to its high strength,good creep resistance,high temperature resistance and wide range of pH applications,it has become the most widely used membrane material in industry.However,due to the strong hydrophobicity of polysulfone,the permeable membrane is easily contaminated,affecting the flux and selectivity of the membrane,thereby reducing the efficiency and service life of the membrane,limiting the application of polysulfone membrane materials in water treatment.Inorganic-organic hybrid membranes are hot research topics for membrane separation in recent years.Adding carbon-based nanomaterials to the polysulfone matrix can combine the excellent performance of carbon-based nanomaterials with polysulfone materials,which can osmotic separation performance can be significantly improved.Using the above principles,this paper studies the preparation and performance of carbon-based nanomaterials,polysulfone composite membranes and composite fiber membranes.The results are as follows:1.The modified Hummers method was used to prepare graphene oxide?GO?,and then the modified Fe₃O₄ nanoparticles were loaded on GO through an amide reaction to prepare magnetic graphene oxide?MGO?.The results show that there are a large number of oxygen-containing functional groups in the GO structure prepared by chemical methods,and the degree of structural order is low.Fe₃O₄ nanoparticles prepared by ultrasonic co-precipitation method have smaller size and better size distribution,and when the reaction temperature is 30?,the prepared Fe₃O₄nanoparticles have a smaller particle size,about 7-13nm and regularity is better.After modification,Fe₃O₄ nanoparticles have amino groups,and successfully reacted with graphene oxide to prepare MGO.2.Add MGO to the polysulfone casting membrane solution,and after a specific magnetic field treatment,prepare a composite polysulfone membrane by immersion gel phase inversion.The study found that there are a large number of membrane pores on the surface of the composite membrane,and the cross section is a typical asymmetric structure.After adding the hydrophilic filler,the volume of the pore structure of the supporting layer decreases,and the finger-like pores change to the honeycomb pores and the pore walls become thinner.Compared with the PSF membrane,as the amount of MGO increases,the water contact angle of the composite membrane decreases from56.3°to 41.8°.The permeation flux of PSF-GO membrane,MGO-1 membrane,MGO-2 membrane and MGO-3 membrane increased by 163.5%,67%,138.7%,184.5%,and they all have the ability to retain PEG-2000.3.Disperse graphene oxide and modified carbon nanotubes?G-CNTs?in polysulfone casting solution in different proportions,and prepare composite polysulfone membrane by immersion gel phase inversion method.The results show that the modified carbon nanotubes have good size and size distribution,high degree of bending and entanglement,and a large number of oxygen-containing functional groups in the structure.The cross-section of the composite membrane is an asymmetric structure.As the proportion of modified carbon nanotubes increases,the thickness of the separation layer of the composite membrane increases and the density increases.With the increase of graphene oxide in the added amount,the volume of the pore structure of the support layer decreases,and the finger-like pores change to the honeycomb pores and the pore walls become thinner.As the proportion of graphene oxide in the added amount increased,the water contact angle of the composite membrane decreased from 64.9°to46.8°compared to the pure membrane.The rejection rate of the composite membrane to PEG-2000 is more than 90%.When the addition ratio of graphene oxide and modified carbon nanotubes is 2:1,the permeation flux of the composite membrane increases from 9.92L/?m²·h?to 33.25L/?m²·h?,an increase of 235%,showing the best osmotic separation performance.4.Add graphene oxide to the polysulfone spinning solution to prepare composite fibers and fiber membranes by electrostatic spinning.The results of the study indicate that the selection of polysulfone with a mass fraction of 20%,an electric field voltage of 35kV,a receiving distance of 20cm,and a solution advancing speed of 0.8 m L/h can produce an ideal composite fiber structure.