Preparation Of Conductive Ceramic Microfiltration Membrane And Its Ion Separation Performance In The Existence Of Auxiliary Electric Field

Membrane separation technology is known as the water treatment technology of the 21st century,is the most rapidly and the most widely used technology in nearly 40 years development.Ultrafiltration membrane and nanofiltration membrane separation technology are used to separate waste water containing ions and salts matter at home and abroad nowadays.In spite of the optimization of operating conditions,this kind of porous membrane perform better performance of ion intercept in separation performance,but because of its shortcomings in small aperture,big membrane resistance,high operating pressure required,small permeate flux and poor ability to resist pollution,lead to this kind of membrane separation technology large energy consumption and low efficiency problems in water treatment process,restrict membrane technology used in industrial application of separation of ion and salt solution.This article is intended for the existing membrane technology of large energy consumption in water ion separation and low efficiency,innovative propose using composite conductive material La0.7Ca0.3CrO3/Al2O3 to prepare conductive microfiltration ceramic membrane,and on the manufacturing technology research basis of conductive microfiltration ceramic membrane,ion separation performance was studied preliminary.The main results are as follows:(1)Composite conductive powder La0.7Ca0.3CrO3/Al2O3 with d50 4.6?m with solid phase method is used to prepare the microfiltration membrane support body.Study the influence of microfiltration membrane support body performance with different addition of Al2O3 and firing temperature,The results show that:As the increasing addition of Al2O3 and firing temperature,the generated random crystal of LCCs.s?Al2(1-x)Cr2xO3 and LHAs.s will increasing,sample sintering degree increasing.When the addition of Al2O3 increasing from 0 to 50%,Flexural strength,shrinkage rate,conductivity decreases gradually,while the porosity,average pore diameter and the pure water flux,corrosion resistance increase gradually.When the sintering temperature is 1350?1600?,the flexural strength,shrinkage rate,average pore diameter,conductivity,corrosion resistance all showed a trend of increase,the porosity and water flux decreased gradually.When the Al2O3 content is 30%,the sintering temperature is 1550?,prepare relatively high folding strength(24.62 Mpa),shrinkage rate(6.87%)and porosity(43.39%),and relatively low average pore diameter(d50 1.80?m),water flux(2.30m3/(m2.h.bar))and electrical conductivity(0.12S/m)microfiltration membrane support body.(2)The top film slurry solids,dip coating time,number of dip coating,pulp powder particle size and sintering temperature are important factors affecting membrane layer thickness,aperture and the pure water flux.Composite conductive powder La0.7Ca0.3CrO3/Al2O3 with d50 0.45?m with sol-gel method used to prepare microfiltration membrane membrane layer.The results show:When the pulp powder particle size d50=0.45?m,solid content is 15%?20%,dip coating coated time for 25?35s,dip-coating times for 2?3 times,sintering temperature of 1400?1500?preservation 2h,can get micro filtration separation membrane layer of excellent support body combine,narrow pore size distribution(0.2?0.28?m),lower pure water flux(1.13?1.77m3/m2.h.bar)and membrane layer thickness of 60?69?m.(3)Under the supporting role of plus low voltage electric field(0?7V),When the conductive ceramic microfiltration membrane in acidic solution,it show up larger ion intercept rate,increasing from 10%under no electric field significantly increase up to more than70%.When the increase of operating pressure,ion concentration,ion intercept rate decreases,at the same time the voltage of electric field and film thickness increase,the decrease of the roof membrane aperture,the ion intercept rate increases accordingly.Integrated optimization solution ion separation conditions,Composite conductive powder La0.7Ca0.3CrO3/Al2O3 with the average aperture membrane layer of d50 0.2?m and membrane layer thickness of 69?m under the applied voltage of 7V,concentration of CaCl2 solution is 1mmol.L-1,pH value of 3,solution operating pressure is 0.15 MPa,ion intercept rate reached 73.5%,solution filtration flux is 0.87 m3/m2.h.bar...