Preparation Of Graphene-polyacrylonitrile Conductive Microfiltration Membrane And Its Electro-filtration Performance

Conductive membranes show great promise in water treatment,and they are able to overcome some of the limitations of conventional membranes.In order to prepare conductive films with excellent performance and high electrical conductivity,it is necessary to develop suitable materials for preparing conductive films.Graphene-based materials,as special conductive materials,have been used in pressure-and electric-driven membrane processes.This paper adopted the method of ultrasonic-assisted anode electrochemical exfoliation of graphene to prepare water-dispersible graphene solution.The next step was to load graphene(Gr)onto a polyacrylonitrile(PAN)bottom membrane by vacuum filtration to prepare Gr/PAN conductive microfiltration membranes,that were used in the electrofiltration process.The effects of preparation conditions on the antifouling properties of graphene and Gr/PAN conductive microfiltration membranes were investigated.In this paper,the water-dispersible graphene solution was prepared by electrochemical anode exfoliation of graphene under the assistance of ultrasound.The graphene was loaded on the polyacrylonitrile membrane by vacuum filtration to prepare the surface hydrophilic Gr/PAN conductive microfiltration membrane.The structure and properties of membranes were systematically studied.Using 1 g/L yeast suspension as the feed solution,the conductive microporous membrane as the negative electrode,and the titanium sheet as the anode,and the 3 V DC electric field was applied to the membrane surface to explore the effect of graphene loading on the antifouling performance of the membrane.The results show that when the graphene loading on the surface of the polyacrylonitrile membrane is0.03 g,the conductivity of the Gr/PAN conductive microfiltration membrane is 6.43 S/cm,the water contact angle is 64°,and the average pore size is 0.341μm.With the increase of graphene loading on the membrane surface,the membrane flux increases,and the flux under applied electric field can reach 0.38.In order to further explore the effect of graphene preparation conditions on the antifouling performance of conductive microfiltration membranes.The ultrasonic power of ultrasonic-assisted electrochemical exfoliation of graphene was changed,and Gr/PAN conductive microfiltration membranes were prepared under different ultrasonic powers.The effect of ultrasonic power on the antifouling properties of graphene and conductive microfiltration membranes was studied.The experimental results show that when the ultrasonic power increases,the size of graphene decreases and the number of sheets decreases.The defectivity of graphite decreased,because the I_D/I_G value decreased from0.53 to 0.07.The conductivity(12.43 S/cm)of the conductive microfiltration membrane prepared when the ultrasonic power was 100 W was nearly two times higher than that of the conductive microfiltration membrane(6.5 S/cm)prepared when the ultrasonic power was 40 W.When the ultrasonic power is 100 W,the water contact angle of membrane is72°,and the average pore size is 0.745μm.When the ultrasonic power increases,the flux of the membrane increased under the applied electric field was up to 0.52.Studying the power supply voltage on the quality of graphene and the antifouling performance of Gr/PAN conductive microporous membranes.The experimental results show that when the voltage is increased from 6V to 12V,the rate of electrochemical exfoliation of graphene increases,the size of graphene becomes larger,and the interlayer spacing of graphene becomes larger.The I_D/I_G value increases from 0.07 to 0.68,illustrate the defectivity of graphene increases.The electrical conductivity of the Gr/PAN conductive microfiltration membrane prepared at a power supply voltage of 12 V was 7.3 S/cm,the water contact angle was 70°,and the average pore size was 1.310μm.When the supply voltage increases,the flux increases up to 0.54.