Preparation Of Asymmetric Alumina Ceramic Ultrafiltration Membrane By Injection Molding And Its Application

China,as a major producer of Al₂O₃,makes Al₂O₃ raw materials cheap and easy to use and is widely used in various fields.Al₂O₃’s own temperature resistance,corrosion resistance,high strength and high hardness also make it widely used in the preparation of ceramic filter membrane materials.However,for pure Al₂O₃,it is required to be sintered at a temperature above 1700℃ to obtain a ceramic filter membrane material having excellent performance,which makes the preparation cost too high and is not advantageous for industrial utilization.At present,low temperature sintering of Al₂O₃ has become a research hotspot,but the problem of low strength sintering caused by low temperature sintering has not been well solved.Therefore,it is necessary to study a process of preparing a ceramic film by low-temperature sintering to reduce the production cost while obtaining a high-performance ceramic film material.Another major factor limiting the scale of ceramic membranes is the control of the filtration accuracy of ceramic membranes.The ceramic membranes are usually supported by a support with a large pore size,and the powders whose particle size is gradually reduced are used as a transition layer and separation.Layer aggregate to improve the filtration performance of the ceramic membrane.Therefore,the study of the ceramic membrane transition layer and the separation layer process is of great significance for improving the separation performance of the ceramic membrane.In this paper,the Al₂O₃ powder is used as the aggregate,and the solvent,binder,pore former and sintering aid are added to mix uniformly,the moisture in the slurry is removed,and the ceramic membrane support body is prepared by dry pressing process after granulation.The billet is sintered to obtain a large porosity and flux,high mechanical strength,smooth surface,and is suitable as a ceramic membrane carrier prepared as a transition layer and a separation layer film.The study found that the best combination of multi-component sintering aids is MgO+TiO₂+MnO₂+CuO,which are used in 0.5%,2%,1.5%,and 1.5%,respectively.The sintering temperature was lowered to 1450℃ and the holding time was shortened to one hour.The prepared alumina ceramic membrane support had a diameter of 3.6 cm,a thickness of 4 mm,an average pore diameter of 0.5μm,a porosity of 47.11%,and a maximum operating pressure of 0.6 MPa.The compressive strength is 45.9 MPa,and the pure water flux is8521 L·m^-2·h^-1·bar^-1.Then,the Al₂O₃ powder with a median diameter of 3.321μm（solid phase volume fraction of 45%）was used as the raw material,and the PMMA prepolymerized solution with the viscosity of 3000mPa·S prepared by ultrasonic prepolymerization was used as the premix,0.3%PEG2000.As a dispersant,0.5%TiO₂ and 6%MgO are sintering aids to prepare a uniform transition layer slurry,which is coated on the surface of a self-made alumina ceramic membrane support with a pore size of 0.5μm by a coagulation molding process.After curing and sintering,a transition layer having an average pore diameter of 280 nm was prepared.It was also found in the study that the pre-polymerization of MMA by ultrasonication accelerated,and the prepared PMMA prepolymer was less prone to explosion.At the same time,it was also found that the prepolymerization of MMA by microwave was intense,which was caused by the"heating effect"of microwaves.Subsequently,the anti-hard agglomerated alumina having a median diameter of 3.76 nm prepared by a precipitation method is used as a raw material,and the PMMA prepolymerized solution having a viscosity of 3000 mPa·s is a premixed liquid,and a separation layer slurry is coated on the surface of the transition layer,and then passed.Sintering,a ceramic ultrafiltration membrane having an asymmetric structure with an average pore diameter of 70 nm was prepared.The removal rate of turbidity of Jingyuehu Lake is more than 99%,and the removal rates of TOC and UV₂₅₄ are 77.30% and 64.75%,respectively.