Multi Wall Carbon Nanotube And PVC/PVDF Blend Membrane Study On Preparation And Performance Research

Polyvinylidene fluoride is a semi crystalline polymer with high thermal stability,high toughness,strong impact strength and good film forming ability;PVC is the second synthetic resin in the world,and it has high cost performance.However,both PVDF and PVC films havethedisadvantagesofstronghydrophobicityandpoortoughnessof MWCNTs/Fe₃O₄/PVC film,all need to modification;Therefore,use the modified multi wall carbon nanotube?MWCNTs?by Fe₃O₄ with high tensile strength,modulus of elasticity,specific saturation magnetization,superparamagnetic and hydrophilic properties and the modified MWCNTs by SiO₂ with high viscosity and strong mechanical properties to modify the PVDF and PVC membrane.The experiment use the method about mix the high concentration of H₂SO₄ and HNO3?Vs:Vn is 3:1?acidm to modified,ultrasonic hydrothermal method and chemical hydrothermal method to configure MWCNTs/Fe₃O₄ and MWCNTs/Fe₃O₄/SiO₂ solid,then part mix the nanometer particle to PVC/PVDF,PEG,DMAC and manufacturing membrane by phase inversion method,then get MWCNTs/Fe₃O₄/SiO₂/PVC and MWCNTs/Fe₃O₄/PVDF composite membrane.Through carry out the IR infrared characterization about additive and take the characterization and calculation of membrane surface section structure,contact angle,mechanical strength,water flux swelling degree,porosity,average pore size,etc by SEM,contact angle instrument,drawing instrument,results found:Fe₃O₄ can be completely coated on the surface of MWCNTs,producing a large number of carboxyl groups and hydroxyl groups to improve the consistency of MWCNTs;adding to the MWCNTs/Fe₃O₄ and the MWCNTs/Fe₃O₄/SiO₂ can reduce the contact angle of the PVDF?56.65°?and PVC?68.1°?membrane,improve the hydrophilicity of the membrane,enhance the permeability of the membrane,thereby increasing the flux of the PVDF?152.866L·m2/h?and PVC?111L·m2/h?membrane;the additive can improve the swelling degree,average pore size and porosity of the PVDF?286.91%,28.92nm,82%?and PVC?240%,33nm,83%?membrane,thus enhance the filtering capacity of PVDF?59.71%,71.16%,59.1%,76%?and PVC?65.73%,50.98%,41.07%,73.9%?membrane,increase the interception rate of HA,SA,BPA and BSA;in addition,MWCNTs/Fe₃O₄/SiO₂ can enhance the mechanical properties of the PVC film,and the tensile strength?2.09MPa?and elongation?17.01%?are higher than that of the MWCNTs/Fe₃O₄/PVC film.In addition,the membrane was cleaned by NaOH,NaClO,H₂O₂ and ultrasonic,NaOH/H₂O₂ and ultrasonic cleaning,results found:pure NaOH has good cleaning effect on membrane,and the flux recovery rate is about 80%;the pure NaClO has more damage to the cleaning of the membrane,and the membrane flux is more than 2 times as much as the initial;the cleaning effect of low concentration combined cleaning on membrane is the best,up to 90%,therefore,the membrane contaminated by organic pollutants should be cleaned by low concentration combined,and high concentration oxidant should not be used.Through the preparation of multi wall carbon nanotube composite particles loaded with iron oxide and silica,and the blending modification of PVDF and PVC films,it not only lays a theoretical foundation for the preparation of composite membranes with strong hydrophilicity,provides a new membrane treatment method for sewage treatment and water purification,but also provides a new way of thinking for the study of the blend membrane.