Superhydrophobic Modification And Properties Of Microfiltration Membrane

With the deterioration of the environment and the enhancement of people’s awareness of environmental protection,oil-water separation has attracted increasing attention.The common oil-water separation materials have some disadvantages such as low separation efficiency,serious pollution and even pore blocking.In view of the above shortcomings,superhydrophobic microfiltration membranes were prepared by blending modification and surface modification respectively.In the study,the hydrophobic properties and permeability of the superhydrophobic microfiltration membrane were investigated,and the separation performance of the water-in-oil emulsion with smaller particle size was studied.Major researches in this paper are as follows:Firstly,Superhydrophobic iPP/TiO2 hybrid membranes were prepared by blending modification.The effect of solid content and coagulation bath temperature on the structure and properties of the membrane was mainly discussed in the thermal phase separation process.The results showed:The solid content has a significant effect on the membrane structure.When the solid content is low,the membrane is a bicontinuous structure,and the average pore size is the largest,meanwhile the permeation flux reaches the maximum.The coagulation bath temperature affects the cooling rate and has a significant effect on the membrane performance.As the temperature of the coagulation bath rises,the membrane structure becomes a bicontinuous structure with good connectivity,the average pore diameter increases,and the permeation flux increases.Further,we explored the effect of TiO2 content on the performance of hybrid membranes.The chemical composition of the hybrid membrane was characterized by ATR-FTIR and XRD.The results showed that TiO2 nanoparticles were successfully introduced into the iPP/TiO2 hybrid membrane after blending modification.The average pore size,hydrophobicity and mechanical properties of the membrane were tested respectively,and the petroleum ether permeation flux of the hybrid membrane was investigated.The results showed that when the addition amount of TiO2 nanoparticles is 0.5%,the average pore size of the membrane increases,and the hydrophobicity of the membrane is enhanced so that its water contact angle increases from 120° to about 150°;The permeation flux of the hybrid membrane reached 150%of the pure membrane flux.The kerosene emulsion was used to evaluate the oil-water separation performance of the hybrid membrane.The oil-water separation test proved that the iPP/TiO2 hybrid membrane has a good separation effect on the water-in-oil emulsion,and the droplet size in the filtrate decreased obviously to nanometer level.Secondly,a superhydrophobic TiO2&POTS@PP membrane was prepared by surface modification.The hydrophilic TiO2 nanoparticles were fixed on the surface of the membrane by E51,and the surface modification of the membrane was achieved by crosslinking POTS with TiO2 nanoparticles to obtain superhydrophobic TiO2&POTS@PP membrane.The effect of the TiO2 concentration,POTS concentration and reaction time on the hydrophobic properties of the membrane was investigated.The surface morphology of the membrane was characterized by SEM.It was found that the TiO2 nanoparticles were uniformly dispersed on the surface and section of the membrane without pore blocking.The TiO2&POTS@PP membranes were characterized by ATR-FTIR,XPS and EDX.The results show that the TiO2 nanoparticles and POTS were successfully introduced into the surface and cross section of the membrane.The chemical stability test of the membrane showed that the TiO2&POTS@PP membrane has good acid resistance.Finally,the TiO2&POTS@PP membrane was used for the separation of various water-in-oil emulsions,showing excellent separation and the water content in the filtrate was significantly reduced.