Effect Of Electric Field On Properties Of Flat Ceramic Film And PVDF Film

Water shortage is a global problem faced by human society throughout developm ent process.Water purification and reuse are the key methods im portant means to alleviate this problem.Membrane separation technology has been widely applied in water treatm ent industry in recent years due to its simple technology,high automation and high effluent quality.However,the application of membrane technology in water treatment is limited by membrane fouling.To control the irreversible pore blockage fouling is the core issue in membrane water treatment.In this paper,the electrocoagulation membrane reactor(ECMR)is used,Put the ceramic membrane module of microfiltration plate in the electric field area of electrochemical system,study the removal effect of humic acid by the synergistic effect of flocculation and electric field,the alleviation of membrane pollution,and the change degree of electric field on the pollution of ceramic membrane and PVDF membrane.The removal efficiency of ECMR(built-in flat ceramic membrane)is 88.3%when HA concentration in water is 5 mg·L-1.It can effectively remove HA from water,its removal efficiency is significantly higher than EC-MF,MF and EC.The optimal process parameters of ECMR(built-in flat ceramic membrane)are:current density 10 A·m-2,initial pH 7,initial conductivity 1000μS·cm-1,electrolysis time 30 min,the membrane flux is stable between 93%-95%.Moreover,higher current density and weak acid pH are beneficial to improve membrane flux.Compared with the EC-MF flat ceramic membrane,the time to reach steady state is increased by 7min,the flux is nearly 20%higher,the porosity is increased by 20%,and the time to reach stability is shorter.Characterization of the new film,the contaminated film,and the filter cake layer on the surface of the cleaned membrane revealed that the contents of aluminum and silicon elements on the surface of the contaminated film increased significantly.The attenuation of the membrane flux is due to the flocs formed by the combination of the hydrolysates of aluminum ions with humic acid and kaolin through adsorption,neutralization and net sweeping,which are adsorbed in the membrane pores or deposited on the membrane surface to form membrane pollution.After cleaning,the membrane flux was restored to 0.97 times the initial value.After cleaning,the membrane can be reused and the membrane fouling is reversible.ECMR(built-in flat ceramic membrane)can realize the synergistic effect of flocculation and electric field,which can reduce membrane pollution and improve water quality.Compared with the hollow fiber(PVDF)membrane module used in the past,the flat ceramic membrane has a long service life,high mechanical strength and easy cleaning.The comparison of the anti-fouling performance of the two membranes by the electric field in the ECMR device is shown.The results show that:compared with PVDF membrane,flat ceramic membrane can reduce membrane fouling and improve membrane flux in a short time.The electric field increased the porosity of the filter cake layer.Under the action of the electric field,the porosity of the flat ceramic membrane increased more than that of the PVDF membrane.Flat ceramic membranes are more resistant to contamination than PVDF membranes,which provides more water flux.The electric field intensity increases,the membrane flux increases,and the hydrophilicity increases.Under the condition that the electric field strength increases the same,the hydrophobicity of the flat ceramic membrane decreases more than that of the PVDF membrane,thereby increasing the larger membrane flux.The energy consumption of the flat ceramic film and PVDF film is as follows:ECMR flat ceramic film,ECMR PVDF film,EC-MF flat ceramic film,and EC-PVDF film.Compared with PVDF,the flat ceramic membrane used in the ECMR device has reduced energy consumption per cubic meter by 0.09KWh.The electric field has a greater impact on the reduction of flat ceramic membrane energy consumption than PVDF membrane.