Preparation And Study Of Multi-functional Ceramic Membrane And Support

With the rapid development of industrialization,the pollution problem of water environments is becoming more and more serious.The traditional methods for water treatment have some limitations and low efficiency.Therefore,the development of efficient,energy-saving and pollution-free water treatment technology is the key to solve the current water treatment.Ceramic membranes play a great role in the industrial fields due to their high separation efficiency,stable effect,good chemical stability,acid and alkali resistance,organic solvent resistance,bacteria,high temperature resistance,anti pollution,high mechanical strength,good regeneration performance,simple separation process,low energy consumption,easy operation and maintenance,long service life and many other advantages.However,the current preparation of titanate ceramic membrane is very expensive and high energy consumption.Furthermore,aluminum titanate ceramic has low structural strength and the potassium hexatitanate whisker synthesis is long time consuming,which is not conducive to environmental protection.Therefore,current research focuses on how to improve technology and selecting suitable additives to reduce support costs and to improve its performances like the simultaneously high permeability and photocatalysis.This dissertation deals with the preparing of high performance aluminum titanate porous support using attapulgite as additive and the synthesis of six potassium titanate whisker utilizing epoxy propane as gel driving agent by sol-gel method.The multifunctional ceramic membrane was also made by sol-gel method with self-made support.At present,the following progresses have been addressed:1.Al₂O₃ and TiO₂ were used as raw materials to prepare aluminum titanate ceramics by sintering process.The reaction conditions were designed as different amounts of attapulgite additives and sintering at different temperatures.The crystalline phase composition,morphology and porosity of the sintered body were characterized respectively.The experimental results show that adding attapulgite can form the reinforced phase of mullite and magnesium titanate in the sintering process,and improve the properties of aluminum titanate.The maximum pore diameter and the average pore size increased with the increased of the dosage.When the additive amount was 25%and the sintering temperature was 1300^o C,the porous aluminium titanate ceramic could achieve the best performance,the sample shows the open porosity of 32.41%and the three point bending strength of 45.48 MPa.2.Using titanium chloride and potassium acetate as raw material,and propylene oxide as gel driving agent,potassium titanate whiskers were prepared by sol-gel method and two step method.The results show that the two methods can effectively reduce the synthesis temperature of ceramic whiskers.The quality of whiskers prepared by one step method was better than that of prepared by the two step method in morphology,length to diameter ratio,and dispersion.The average diameter of whiskers was 0.3?m,and the length diameter ratio?L/D?reached 12,the thickness and uniformity were good,and the dispersibility was good by one-step process,when the ratio of titanium to potassium was 2.5,the sintering temperature was 900^oC and the holding time was 3 h.3.The ceramic membrane tube was selected as self-made porous aluminum titanate ceramic tube,the combining sol-gel method and impregnation and pulling process were applied to coat the support surface.The experimental results show that the sintering temperature has a great influence on the porosity,water flux,bending strength and photocatalytic properties of the ceramic membrane.The optimum condition of composite membrane is heat treatment at 900^oC,the porosity of ceramic membrane tube is 20.47%and the bending strength is 70.12 MPa;Under the irradiation of ultraviolet light,the degradation of modeling pollute target TC can be decomposed within one hour.